1
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Huang Y, Liang Z, Zeng J, Yuan J. Nonideal effects on ionization potential depression and ionization balance in dense Al and Au plasmas. Phys Rev E 2024; 109:045210. [PMID: 38755935 DOI: 10.1103/physreve.109.045210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Accepted: 04/04/2024] [Indexed: 05/18/2024]
Abstract
For low-density plasmas, the ionization balance can be properly described by the normal Saha equation in the chemical picture. For dense plasmas, however, nonideal effects due to the interactions between the electrons and ions and among the electrons themselves affect the ionization potential depression and the ionization balance. With the increasing of plasma density, the pressure ionization starts to play a more obvious role and competes with the thermal ionization. Based on a local-density temperature-dependent ion-sphere model, we develop a unified and self-consistent theoretical formalism to simultaneously investigate the ionization potential depression, the ionization balance, and the charge states distributions of the dense plasmas. In this work, we choose Al and Au plasmas as examples as Al is a prototype light element and Au is an important heavy element in many research fields such as in the inertial confinement fusion. The nonideal effect of the free electrons in the plasmas is considered by the single-electron effective potential contributed by both the bound electrons of different charge states and the free electrons in the plasmas. For the Al plasmas, we can reconcile the results of two experiments on measuring the ionization potential depression, in which one experiment can be better explained by the Stewart-Pyatt model while the other fits better with the Ecker-Kröll model. For dense Au plasmas, the results show that the double peak structure of the charge state distribution appears to be a common phenomenon. In particular, the calculated ionization balance shows that the two- and three-peak structures can appear simultaneously for denser Au plasmas above ∼30g/cm^{3}.
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Affiliation(s)
- Yihua Huang
- College of Science, Zhejiang University of Technology, Hangzhou Zhejiang 310023, People's Republic of China
| | - Zhenhao Liang
- College of Science, Zhejiang University of Technology, Hangzhou Zhejiang 310023, People's Republic of China
| | - Jiaolong Zeng
- College of Science, Zhejiang University of Technology, Hangzhou Zhejiang 310023, People's Republic of China
| | - Jianmin Yuan
- Institute of Atomic and Molecular Physics, Jilin University, Changchun Jilin 130012, People's Republic of China
- Graduate School of China Academy of Engineering Physics, Beijing 100193, People's Republic of China
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2
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Pérez-Callejo G, Gawne T, Preston TR, Hollebon P, Humphries OS, Chung HK, Dakovski GL, Krzywinski J, Minitti MP, Burian T, Chalupský J, Hájková V, Juha L, Vozda V, Zastrau U, Vinko SM, Rose SJ, Wark JS. Dielectronic satellite emission from a solid-density Mg plasma: Relationship to models of ionization potential depression. Phys Rev E 2024; 109:045204. [PMID: 38755888 DOI: 10.1103/physreve.109.045204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Accepted: 03/01/2024] [Indexed: 05/18/2024]
Abstract
We report on experiments where solid-density Mg plasmas are created by heating with the focused output of the Linac Coherent Light Source x-ray free-electron laser. We study the K-shell emission from the helium- and lithium-like ions using Bragg crystal spectroscopy. Observation of the dielectronic satellites in lithium-like ions confirms that the M-shell electrons appear bound for these high charge states. An analysis of the intensity of these satellites indicates that when modeled with an atomic-kinetics code, the ionization potential depression model employed needs to produce depressions for these ions which lie between those predicted by the well known Stewart-Pyatt and Ecker-Kroll models. These results are largely consistent with recent density functional theory calculations.
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Affiliation(s)
- G Pérez-Callejo
- Departamento de Física Teórica Atómica y Óptica, Universidad de Valladolid, 47011 Valladolid, Spain
| | - T Gawne
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - T R Preston
- European XFEL GmbH, Holzkoppel 4, 22869 Schenefeld, Germany
| | - P Hollebon
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - O S Humphries
- European XFEL GmbH, Holzkoppel 4, 22869 Schenefeld, Germany
| | - H-K Chung
- Korea Institute of Fusion Energy (KFE), Daejeon 34133, South Korea
| | - G L Dakovski
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - J Krzywinski
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - M P Minitti
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - T Burian
- Department of Radiation and Chemical Physics, Institute of Physics, Czech Academy of Sciences, Na Slovance 2, 182 21 Prague 8, Czech Republic
| | - J Chalupský
- Department of Radiation and Chemical Physics, Institute of Physics, Czech Academy of Sciences, Na Slovance 2, 182 21 Prague 8, Czech Republic
| | - V Hájková
- Department of Radiation and Chemical Physics, Institute of Physics, Czech Academy of Sciences, Na Slovance 2, 182 21 Prague 8, Czech Republic
| | - L Juha
- Department of Radiation and Chemical Physics, Institute of Physics, Czech Academy of Sciences, Na Slovance 2, 182 21 Prague 8, Czech Republic
| | - V Vozda
- Department of Radiation and Chemical Physics, Institute of Physics, Czech Academy of Sciences, Na Slovance 2, 182 21 Prague 8, Czech Republic
| | - U Zastrau
- European XFEL GmbH, Holzkoppel 4, 22869 Schenefeld, Germany
| | - S M Vinko
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom
| | - S J Rose
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
- Plasma Physics Group, The Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2AZ, United Kingdom
| | - J S Wark
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
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3
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Cho MS, Chung HK, Foord ME, Libby SB, Cho BI. Numerical investigation of nonequilibrium electron effects on the collisional ionization rate in the collisional-radiative model. Phys Rev E 2024; 109:045207. [PMID: 38755933 DOI: 10.1103/physreve.109.045207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2024] [Accepted: 03/21/2024] [Indexed: 05/18/2024]
Abstract
The interplay of kinetic electron physics and atomic processes in ultrashort laser-plasma interactions provides a comprehensive understanding of the impact of the electron energy distribution on plasma properties. Notably, nonequilibrium electrons play a vital role in collisional ionization, influencing ionization degrees and spectra. This paper introduces a computational model that integrates the physics of kinetic electrons and atomic processes, utilizing a Boltzmann equation for nonequilibrium electrons and a collisional-radiative model for atomic state populations. The model is used to investigate the influence of nonequilibrium electrons on collisional ionization rates and its effect on the population distribution, as observed in a widely known experiment [Young et al., Nature (London) 466, 56 (2010)0028-083610.1038/nature09177]. The study reveals a significant nonequilibrium electron presence during XFEL-matter interactions, profoundly affecting collisional ionization rates in the gas plasma, thereby necessitating careful consideration of the Collisional-Radiative model applied to such systems.
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Affiliation(s)
- M S Cho
- Gwangju Institute of Science and Technology, Department of Physics and Photon Science, Gwangju 61005, South Korea
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550, USA
| | - H-K Chung
- Korea Institute of Fusion Energy, Daejeon 34133, South Korea
| | - M E Foord
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550, USA
| | - S B Libby
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, California 94550, USA
| | - B I Cho
- Gwangju Institute of Science and Technology, Department of Physics and Photon Science, Gwangju 61005, South Korea
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4
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Starrett CE, Thelen TQ, Fontes CJ, Rehn DA. Excited states in warm and hot dense matter. Phys Rev E 2024; 109:035201. [PMID: 38632718 DOI: 10.1103/physreve.109.035201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Accepted: 02/06/2024] [Indexed: 04/19/2024]
Abstract
Accurate modeling of warm and hot dense matter is challenging in part due to the multitude of excited states that must be considered. Here, we present a variational framework that models these excited states. In this framework an excited state is defined by a set of effective one-electron occupation factors, and the corresponding energy is defined by the effective one-body energy with an exchange and correlation term. The variational framework is applied to an atom-in-plasma model (a generalization of the so-called average atom model). Comparisons with a density functional theory based average atom model generally reveal good agreement in the calculated pressure, but our model also gives access to the excitation energies and charge state distributions.
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Affiliation(s)
- C E Starrett
- Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, New Mexico 87545, USA
| | - T Q Thelen
- Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, New Mexico 87545, USA
| | - C J Fontes
- Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, New Mexico 87545, USA
| | - D A Rehn
- Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, New Mexico 87545, USA
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5
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Gawne T, Vinko SM, Wark JS. Quantifying ionization in hot dense plasmas. Phys Rev E 2024; 109:L023201. [PMID: 38491590 DOI: 10.1103/physreve.109.l023201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 12/07/2023] [Indexed: 03/18/2024]
Abstract
Ionization is a problematic quantity in that it does not have a well-defined thermodynamic definition and yet it is a key parameter within plasma modeling. One still therefore aims to find a consistent and unambiguous definition for the ionization state. Within this context we present finite-temperature density functional theory calculations of the ionization state of carbon in CH plasmas using two potential definitions: one based on counting the number of continuum electrons, and another based on the optical conductivity. Differences of up to 10% are observed between the two methods. However, including "Pauli forbidden" transitions in the conductivity reproduces the counting definition, suggesting such transitions are important to evaluate the ionization state.
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Affiliation(s)
- Thomas Gawne
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - Sam M Vinko
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom
| | - Justin S Wark
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
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6
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Gawne T, Campbell T, Forte A, Hollebon P, Perez-Callejo G, Humphries OS, Karnbach O, Kasim MF, Preston TR, Lee HJ, Miscampbell A, van den Berg QY, Nagler B, Ren S, Royle RB, Wark JS, Vinko SM. Investigating mechanisms of state localization in highly ionized dense plasmas. Phys Rev E 2023; 108:035210. [PMID: 37849197 DOI: 10.1103/physreve.108.035210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Accepted: 08/11/2023] [Indexed: 10/19/2023]
Abstract
We present experimental observations of K_{β} emission from highly charged Mg ions at solid density, driven by intense x rays from a free electron laser. The presence of K_{β} emission indicates the n=3 atomic shell is relocalized for high charge states, providing an upper constraint on the depression of the ionization potential. We explore the process of state relocalization in dense plasmas from first principles using finite-temperature density functional theory alongside a wave-function localization metric, and find excellent agreement with experimental results.
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Affiliation(s)
- Thomas Gawne
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - Thomas Campbell
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - Alessandro Forte
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - Patrick Hollebon
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - Gabriel Perez-Callejo
- Departamento de Física Teórica, Atómica y Óptica, Universidad de Valladolid, Valladolid, Spain
| | | | - Oliver Karnbach
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - Muhammad F Kasim
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | | | - Hae Ja Lee
- SLAC National Accelerator Laboratory, 2575 Sand Hill Rd, Menlo Park, California 94025, USA
| | - Alan Miscampbell
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - Quincy Y van den Berg
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - Bob Nagler
- SLAC National Accelerator Laboratory, 2575 Sand Hill Rd, Menlo Park, California 94025, USA
| | - Shenyuan Ren
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - Ryan B Royle
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - Justin S Wark
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - Sam M Vinko
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Didcot OX11 0QX, United Kingdom
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7
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Benredjem D, Pain JC, Calisti A, Ferri S. Plasma density effects on electron impact ionization. Phys Rev E 2023; 108:035207. [PMID: 37849189 DOI: 10.1103/physreve.108.035207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 08/15/2023] [Indexed: 10/19/2023]
Abstract
We present new results on ionization by electron impacts in a dense plasma. We are interested in the density effect known as ionization potential depression and its role in atomic structure. Rather than using the well-known Stewart-Pyatt or Ecker-Kröll formulas for the ionization potential depression, we consider a distribution function of the ionization energy, which involves the plasma fluctuations due to ion dynamics. This distribution is calculated within classical molecular dynamics. The removal of the noise yields a new distribution which is composed of a small set of Gaussian peaks among which one peak is selected by considering the signal-to-noise ratio. This approach provides an ionization potential depression in good agreement with experimental results obtained at the Linac Coherent Light Source facility. Our results are also compared with other calculations. In a second part, we investigate the effects of the ionization potential depression and the fluctuations on ionization by electron impacts. We propose an expression of the cross section that is based on an average over the ionization energy distribution. This cross section can be calculated analytically. The main strength of our work is to account for the fluctuations due to ion dynamics.
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Affiliation(s)
- Djamel Benredjem
- Université Paris-Saclay, CNRS, Laboratoire Aimé Cotton, F-91405 Orsay, France
| | - Jean-Christophe Pain
- CEA, DAM, DIF, F-91297 Arpajon, France and Université Paris-Saclay, CEA, Laboratoire Matière en Conditions Extrêmes, 91680 Bruyères-le-Châtel Cedex, France
| | - Annette Calisti
- Aix-Marseille Université, CNRS, Physique des Interactions Ioniques et Moléculaires, Campus Saint-Jérôme, 13397 Marseille Cedex 20, France
| | - Sandrine Ferri
- Aix-Marseille Université, CNRS, Physique des Interactions Ioniques et Moléculaires, Campus Saint-Jérôme, 13397 Marseille Cedex 20, France
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8
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Ren S, Vinko S, Wark JS. Simulations of collisional effects in an inner-shell solid-density Mg X-ray laser. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2023; 381:20220218. [PMID: 37393935 DOI: 10.1098/rsta.2022.0218] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Accepted: 01/26/2023] [Indexed: 07/04/2023]
Abstract
Inner-shell [Formula: see text] X-ray lasers have been created by pumping gaseous, solid, and liquid targets with the intense X-ray output of free-electron lasers (FELs). For gaseous targets lasing relies on the creation of [Formula: see text]-shell core holes on a time-scale short compared with filling via Auger decay. In the case of solid and liquid density systems, collisional effects will also be important, affecting not only populations but also line-widths, both of which impact the degree of overall gain, and its duration. However, to date, such collisional effects have not been extensively studied. We present here initial simulations using the CCFLY code of inner-shell lasing in solid-density Mg, where we self-consistently treat the effects of the incoming FEL radiation and the atomic kinetics of the Mg system, including radiative, Auger and collisional effects. We find that the combination of collisional population of the lower states of the lasing transitions and broadening of the lines precludes lasing on all but the [Formula: see text] of the initially cold system. Even assuming instantaneous turning on of the FEL pump, we find the duration of the gain in the solid system to be sub-femtosecond. This article is part of the theme issue 'Dynamic and transient processes in warm dense matter'.
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Affiliation(s)
- Shenyuan Ren
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, UK
| | - Sam Vinko
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, UK
| | - Justin S Wark
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, UK
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9
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Zeng J, Li Y, Hou Y, Yuan J. Nonideal effect of free electrons on ionization equilibrium and radiative property in dense plasmas. Phys Rev E 2023; 107:L033201. [PMID: 37072979 DOI: 10.1103/physreve.107.l033201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 02/26/2023] [Indexed: 04/20/2023]
Abstract
The thermodynamic as well as optical properties of strongly coupled plasmas depend crucially on the average degree of ionization and the ionic state composition, which, however, cannot be determined by using the normal Saha equation usually used for the ideal plasmas. Hence, an adequate treatment of the ionization balance and the charge state distribution of strongly coupled plasmas is still a challenge for theory due to the interactions between the electrons and ions and among the electrons themselves. Based on a local density temperature-dependent ion-sphere model, the Saha equation approach is extended to the regime of strongly coupled plasmas by taking into account the free-electron-ion interaction, the free-free-electron interaction, the nonuniform free-electron space distribution, and the free-electron quantum partial degeneracy. All the quantities, including the bound orbitals with ionization potential depression, free-electron distribution, and bound and free-electron partition function contributions, are calculated self-consistently in the theoretical formalism. This study shows that the ionization equilibrium is evidently modified by considering the above nonideal characteristics of the free electrons. Our theoretical formalism is validated by the explanation of a recent experimental measurement of the opacity of dense hydrocarbon.
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Affiliation(s)
- Jiaolong Zeng
- College of Science, Zhejiang University of Technology, Hangzhou Zhejiang 310023, People's Republic of China
- College of Science, National University of Defense Technology, Changsha Hunan 410073, People's Republic of China
| | - Yongjun Li
- College of Science, National University of Defense Technology, Changsha Hunan 410073, People's Republic of China
| | - Yong Hou
- College of Science, National University of Defense Technology, Changsha Hunan 410073, People's Republic of China
| | - Jianmin Yuan
- College of Science, National University of Defense Technology, Changsha Hunan 410073, People's Republic of China
- Graduate School of China Academy of Engineering Physics, Beijing 100193, People's Republic of China
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10
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Cardoch S, Trost F, Scott HA, Chapman HN, Caleman C, Timneanu N. Decreasing ultrafast x-ray pulse durations with saturable absorption and resonant transitions. Phys Rev E 2023; 107:015205. [PMID: 36797944 DOI: 10.1103/physreve.107.015205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Accepted: 12/09/2022] [Indexed: 01/19/2023]
Abstract
Saturable absorption is a nonlinear effect where a material's ability to absorb light is frustrated due to a high influx of photons and the creation of electron vacancies. Experimentally induced saturable absorption in copper revealed a reduction in the temporal duration of transmitted x-ray laser pulses, but a detailed account of changes in opacity and emergence of resonances is still missing. In this computational work, we employ nonlocal thermodynamic equilibrium plasma simulations to study the interaction of femtosecond x rays and copper. Following the onset of frustrated absorption, we find that a K-M resonant transition occurring at highly charged states turns copper opaque again. The changes in absorption generate a transient transparent window responsible for the shortened transmission signal. We also propose using fluorescence induced by the incident beam as an alternative source to achieve shorter x-ray pulses. Intense femtosecond x rays are valuable to probe the structure and dynamics of biological samples or to reach extreme states of matter. Shortened pulses could be relevant for emerging imaging techniques.
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Affiliation(s)
- Sebastian Cardoch
- Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden
| | - Fabian Trost
- Center for Free-Electron Laser Science CFEL, Deutsches-Elektronen Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
| | - Howard A Scott
- Lawrence Livermore National Laboratory, L-18, P.O. Box 808, Livermore, California 94550, USA
| | - Henry N Chapman
- Center for Free-Electron Laser Science CFEL, Deutsches-Elektronen Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany.,The Hamburg Center for Ultrafast Imaging, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany.,Department of Physics, Universität Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Carl Caleman
- Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden.,Center for Free-Electron Laser Science CFEL, Deutsches-Elektronen Synchrotron DESY, Notkestr. 85, 22607 Hamburg, Germany
| | - Nicusor Timneanu
- Department of Physics and Astronomy, Uppsala University, Box 516, SE-751 20 Uppsala, Sweden
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11
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Hu SX, Bishel DT, Chin DA, Nilson PM, Karasiev VV, Golovkin IE, Gu M, Hansen SB, Mihaylov DI, Shaffer NR, Zhang S, Walton T. Probing atomic physics at ultrahigh pressure using laser-driven implosions. Nat Commun 2022; 13:6780. [PMID: 36384992 PMCID: PMC9668816 DOI: 10.1038/s41467-022-34618-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 10/31/2022] [Indexed: 11/17/2022] Open
Abstract
Spectroscopic measurements of dense plasmas at billions of atmospheres provide tests to our fundamental understanding of how matter behaves at extreme conditions. Developing reliable atomic physics models at these conditions, benchmarked by experimental data, is crucial to an improved understanding of radiation transport in both stars and inertial fusion targets. However, detailed spectroscopic measurements at these conditions are rare, and traditional collisional-radiative equilibrium models, based on isolated-atom calculations and ad hoc continuum lowering models, have proved questionable at and beyond solid density. Here we report time-integrated and time-resolved x-ray spectroscopy measurements at several billion atmospheres using laser-driven implosions of Cu-doped targets. We use the imploding shell and its hot core at stagnation to probe the spectral changes of Cu-doped witness layer. These measurements indicate the necessity and viability of modeling dense plasmas with self-consistent methods like density-functional theory, which impact the accuracy of radiation transport simulations used to describe stellar evolution and the design of inertial fusion targets. Atoms and molecules under extreme temperature and pressure can be investigated using dense plasmas achieved by laser-driven implosion. Here the authors report spectral change of copper in billions atmosphere pressure that can only be explained by a self-consistent approach.
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12
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Zhou X, Wei J, Cheng R, Zhang Y, Chen Y, Liang C, Zhang X, Zhao Y. Au L-shell x-ray emission induced by 154.3–423.9 MeV/u C6+ ions. Sci Rep 2022; 12:19264. [DOI: 10.1038/s41598-022-23830-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Accepted: 11/07/2022] [Indexed: 11/12/2022] Open
Abstract
AbstractThe L-shell x-ray emissions of gold are investigated for the bombardment of high energy C6+ ions in the high energy region of 154.3–423.9 MeV/u. Due to the multiple ionization of outer-shell electrons at the movement of L x-ray emission, the blue shift of the experimental x-ray energy and an enhancement of the relative intensity ratios of Lι, Lβ–Lα x rays are observed. Using the improved thin target formula and considering the effect of multiple ionization on atomic parameters, the L-subshell x-ray production cross sections are extracted from the counts and compared with the theoretical estimations of BEA, PWBA and ECPSSR. It is found that the relative corrections of ECPSSR on PWBA can be ignored in the present experimental energy region. The calculations of PWBA and ECPSSR are almost identical and both are larger than the experimental results. The BEA is in better agreement with the experiment as a whole.
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13
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Multi-Configuration Calculation of Ionization Potential Depression. PLASMA 2022. [DOI: 10.3390/plasma5040029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The modelling of ionization potential depression in warm and hot dense plasmas constitutes a real theoretical challenge due to ionic coupling and electron degeneracy effects. In this work, we present a quantum statistical model based on a multi-configuration description of the electronic structure in the framework of Density Functional Theory. We discuss different conceptual issues inherent to the definition of ionization potential depression and compare our results with the famous and widely-used Ecker-Kröll and Stewart-Pyatt models.
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14
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Beier NF, Allison H, Efthimion P, Flippo KA, Gao L, Hansen SB, Hill K, Hollinger R, Logantha M, Musthafa Y, Nedbailo R, Senthilkumaran V, Shepherd R, Shlyaptsev VN, Song H, Wang S, Dollar F, Rocca JJ, Hussein AE. Homogeneous, Micron-Scale High-Energy-Density Matter Generated by Relativistic Laser-Solid Interactions. PHYSICAL REVIEW LETTERS 2022; 129:135001. [PMID: 36206410 DOI: 10.1103/physrevlett.129.135001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 08/01/2022] [Accepted: 08/26/2022] [Indexed: 06/16/2023]
Abstract
Short-pulse, laser-solid interactions provide a unique platform for studying complex high-energy-density matter. We present the first demonstration of solid-density, micron-scale keV plasmas uniformly heated by a high-contrast, 400 nm wavelength laser at intensities up to 2×10^{21} W/cm^{2}. High-resolution spectral analysis of x-ray emission reveals uniform heating up to 3.0 keV over 1 μm depths. Particle-in-cell simulations indicate the production of a uniformly heated keV plasma to depths of 2 μm. The significant bulk heating and presence of highly ionized ions deep within the target are attributed to the few MeV hot electrons that become trapped and undergo refluxing within the target sheath fields. These conditions enabled the differentiation of atomic physics models of ionization potential depression in high-energy-density environments.
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Affiliation(s)
- N F Beier
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta T6G 2R3, Canada
- STROBE, NSF Science and Technology Center, University of California, Irvine, California 92617, USA
| | - H Allison
- STROBE, NSF Science and Technology Center, University of California, Irvine, California 92617, USA
| | - P Efthimion
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08536, USA
| | - K A Flippo
- Los Alamos National Laboratory, P.O. Box 1163, Los Alamos, New Mexico 87545, USA
| | - L Gao
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08536, USA
| | - S B Hansen
- Sandia National Laboratories, Albuquerque, New Mexico 87185, USA
| | - K Hill
- Princeton Plasma Physics Laboratory, Princeton, New Jersey 08536, USA
| | - R Hollinger
- Department of Electrical and Computer Engineering, Colorado State University, Fort Collins, Colorado 80521, USA
| | - M Logantha
- STROBE, NSF Science and Technology Center, University of California, Irvine, California 92617, USA
| | - Y Musthafa
- STROBE, NSF Science and Technology Center, University of California, Irvine, California 92617, USA
| | - R Nedbailo
- Department of Electrical and Computer Engineering, Colorado State University, Fort Collins, Colorado 80521, USA
| | - V Senthilkumaran
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta T6G 2R3, Canada
| | - R Shepherd
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - V N Shlyaptsev
- Department of Electrical and Computer Engineering, Colorado State University, Fort Collins, Colorado 80521, USA
| | - H Song
- Department of Electrical and Computer Engineering, Colorado State University, Fort Collins, Colorado 80521, USA
| | - S Wang
- Department of Electrical and Computer Engineering, Colorado State University, Fort Collins, Colorado 80521, USA
| | - F Dollar
- STROBE, NSF Science and Technology Center, University of California, Irvine, California 92617, USA
| | - J J Rocca
- Department of Electrical and Computer Engineering, Colorado State University, Fort Collins, Colorado 80521, USA
- Department of Physics, Colorado State University, Fort Collins, Colorado 80521, USA
| | - A E Hussein
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta T6G 2R3, Canada
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15
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Jin R, Jurek Z, Santra R, Son SK. Plasma environmental effects in the atomic structure for simulating x-ray free-electron-laser-heated solid-density matter. Phys Rev E 2022; 106:015206. [PMID: 35974549 DOI: 10.1103/physreve.106.015206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 07/08/2022] [Indexed: 06/15/2023]
Abstract
High energy density (HED) matter exists extensively in the Universe, and it can be created with extreme conditions in laboratory facilities such as x-ray free-electron lasers (XFEL). In HED matter, the electronic structure of individual atomic ions is influenced by a dense plasma environment, and one of the most significant phenomena is the ionization potential depression (IPD). Incorporation of the IPD effects is of great importance in accurate modeling of dense plasmas. All theoretical treatments of IPD so far have been based on the assumption of local thermodynamic equilibrium, but its validity is questionable in ultrafast formation dynamics of dense plasmas, particularly when interacting with intense XFEL pulses. A treatment of transient IPD, based on an electronic-structure calculation of an atom in the presence of a plasma environment described by classical particles, has recently been proposed [Phys. Rev. E 103, 023203 (2021)2470-004510.1103/PhysRevE.103.023203], but its application to and impact on plasma dynamics simulations have not been investigated yet. In this work, we extend XMDYN, a hybrid quantum-classical approach combining Monte Carlo and molecular dynamics, by incorporating the proposed IPD treatment into plasma dynamics simulations. We demonstrate the importance of the IPD effects in theoretical modeling of aluminum dense plasmas by comparing two XMDYN simulations: one with electronic-structure calculations of isolated atoms (without IPD) and the other with those of atoms embedded in a plasma (with IPD). At equilibrium, the mean charge obtained in the plasma simulation with IPD is in good agreement with the full quantum-mechanical average-atom model. The present approach promises to be a reliable tool to simulate the creation and nonequilibrium evolution of dense plasmas induced by ultraintense and ultrashort XFEL pulses.
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Affiliation(s)
- Rui Jin
- Center for Free-Electron Laser Science CFEL, Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany
| | - Zoltan Jurek
- Center for Free-Electron Laser Science CFEL, Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany
- The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Robin Santra
- Center for Free-Electron Laser Science CFEL, Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany
- The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany
- Department of Physics, Universität Hamburg, Notkestrasse 9-11, 22607 Hamburg, Germany
| | - Sang-Kil Son
- Center for Free-Electron Laser Science CFEL, Deutsches Elektronen-Synchrotron DESY, Notkestrasse 85, 22607 Hamburg, Germany
- The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany
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16
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Zhou X, Wei J, Cheng R, Liang C, Chen Y, Zhang X, Zhao Y. Multiple ionization of iodine for 2.5-5.0 MeV I 22+ ions impacting on Fe target. Sci Rep 2022; 12:6253. [PMID: 35428756 PMCID: PMC9012858 DOI: 10.1038/s41598-022-10337-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2021] [Accepted: 03/31/2022] [Indexed: 11/25/2022] Open
Abstract
The L-shell X-ray emissions of iodine are investigated as a function of the incident energy for I22+ ions impacting on Fe target in the energy region near the Bohr velocity. Six distinct L-subshell X-rays, Lι, Lα1, 2, Lβ1, 3, 4, Lβ2, 15, Lγ1 and Lγ2, 3, 4, 4', are observed. Compared to the atomic data, the energy of the experimental X ray shifts to the higher energy side. The relative intensity ratios of Lι, Lβ1, 3, 4, Lβ2, 15, to Lα1, 2, Lι to Lβ2, 15 and Lγ2, 3, 4, 4/ to Lγ1 are enhanced, but has no obvious change with the increase of projectile energy in the present energy region. That is interpreted by the multiple ionization effect of the M-, N- and O-shell electrons.
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Affiliation(s)
- Xianming Zhou
- Ion Beam and Optical Physics Joint Laboratory of Xianyang Normal University and IMP, CAS, Xianyang Normal University, Wenlin Rd. 01, XianyangShannxi, 712000, China. .,School of Science, Xi'an Jiaotong University, Xi'an, 710049, China.
| | - Jing Wei
- Ion Beam and Optical Physics Joint Laboratory of Xianyang Normal University and IMP, CAS, Xianyang Normal University, Wenlin Rd. 01, XianyangShannxi, 712000, China
| | - Rui Cheng
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, 730000, China
| | - Changhui Liang
- Ion Beam and Optical Physics Joint Laboratory of Xianyang Normal University and IMP, CAS, Xianyang Normal University, Wenlin Rd. 01, XianyangShannxi, 712000, China
| | - Yanhong Chen
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, 730000, China
| | - Xiaoan Zhang
- Ion Beam and Optical Physics Joint Laboratory of Xianyang Normal University and IMP, CAS, Xianyang Normal University, Wenlin Rd. 01, XianyangShannxi, 712000, China.,Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, 730000, China
| | - Yongtao Zhao
- Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, 730000, China.,School of Science, Xi'an Jiaotong University, Xi'an, 710049, China
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17
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Shaffer NR, Starrett CE. Dense plasma opacity via the multiple-scattering method. Phys Rev E 2022; 105:015203. [PMID: 35193239 DOI: 10.1103/physreve.105.015203] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 12/20/2021] [Indexed: 11/07/2022]
Abstract
The calculation of the optical properties of hot dense plasmas with a model that has self-consistent plasma physics is a grand challenge for high energy density science. Here we exploit a recently developed electronic structure model that uses multiple scattering theory to solve the Kohn-Sham density functional theory equations for dense plasmas. We calculate opacities in this regime, validate the method, and apply it to recent experimental measurements of opacity for Cr, Ni, and Fe. Good agreement is found in the quasicontinuum region for Cr and Ni, while the self-consistent plasma physics of the approach cannot explain the observed difference between models and the experiment for Fe.
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Affiliation(s)
- Nathaniel R Shaffer
- Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, New Mexico 87545, USA and Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623, USA
| | - Charles E Starrett
- Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, New Mexico 87545, USA
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18
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Thermal excitation signals in the inhomogeneous warm dense electron gas. Sci Rep 2022; 12:1093. [PMID: 35058531 PMCID: PMC8776784 DOI: 10.1038/s41598-022-05034-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 12/30/2021] [Indexed: 12/16/2022] Open
Abstract
We investigate the emergence of electronic excitations from the inhomogeneous electronic structure at warm dense matter parameters based on first-principles calculations. The emerging modes are controlled by the imposed perturbation amplitude. They include satellite signals around the standard plasmon feature, transformation of plasmons to optical modes, and double-plasmon modes. These modes exhibit a pronounced dependence on the temperature. This makes them potentially invaluable for the diagnostics of plasma parameters in the warm dense matter regime. We demonstrate that these modes can be probed with present experimental techniques.
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19
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Moldabekov Z, Dornheim T, Böhme M, Vorberger J, Cangi A. The relevance of electronic perturbations in the warm dense electron gas. J Chem Phys 2021; 155:124116. [PMID: 34598570 DOI: 10.1063/5.0062325] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Warm dense matter (WDM) has emerged as one of the frontiers of both experimental physics and theoretical physics and is a challenging traditional concept of plasma, atomic, and condensed-matter physics. While it has become common practice to model correlated electrons in WDM within the framework of Kohn-Sham density functional theory, quantitative benchmarks of exchange-correlation (XC) functionals under WDM conditions are yet incomplete. Here, we present the first assessment of common XC functionals against exact path-integral Monte Carlo calculations of the harmonically perturbed thermal electron gas. This system is directly related to the numerical modeling of x-ray scattering experiments on warm dense samples. Our assessment yields the parameter space where common XC functionals are applicable. More importantly, we pinpoint where the tested XC functionals fail when perturbations on the electronic structure are imposed. We indicate the lack of XC functionals that take into account the needs of WDM physics in terms of perturbed electronic structures.
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Affiliation(s)
- Zhandos Moldabekov
- Center for Advanced Systems Understanding (CASUS), D-02826 Görlitz, Germany
| | - Tobias Dornheim
- Center for Advanced Systems Understanding (CASUS), D-02826 Görlitz, Germany
| | - Maximilian Böhme
- Center for Advanced Systems Understanding (CASUS), D-02826 Görlitz, Germany
| | - Jan Vorberger
- Helmholtz-Zentrum Dresden-Rossendorf (HZDR), D-01328 Dresden, Germany
| | - Attila Cangi
- Center for Advanced Systems Understanding (CASUS), D-02826 Görlitz, Germany
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20
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Zan X, Lin C, Hou Y, Yuan J. Local field correction to ionization potential depression of ions in warm or hot dense matter. Phys Rev E 2021; 104:025203. [PMID: 34525605 DOI: 10.1103/physreve.104.025203] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 07/19/2021] [Indexed: 11/07/2022]
Abstract
An analytical self-consistent approach was recently established to predict the ionization potential depression (IPD) in multicomponent dense plasmas, which is achieved by considering the self-energy of ions and electrons within the quantum statistical theory. In order to explicitly account for the exchange-correlation effect of electrons, we incorporate the effective static approximation of local field correction (LFC) within our IPD framework through the connection of dynamical structure factor. The effective static approximation poses an accurate description for the asymptotic large wave number behavior with the recently developed machine learning representation of static LFC induced from the path-integral Monte Carlo data. Our calculation shows that the introduction of static LFC through dynamical structure factor brings a nontrivial influence on IPD at warm/hot dense matter conditions. The correlation effect within static LFC could provide up to 20% correction to free-electron contribution of IPD in the strong coupling and degeneracy regime. Furthermore, a new screening factor is obtained from the density distribution of free electrons calculated within the average-atom model, with which excellent agreements are observed with other methods and experiments at warm/hot dense matter conditions.
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Affiliation(s)
- Xiaolei Zan
- Department of Physics, College of Liberal Arts and Sciences, National University of Defense Technology, Changsha, Hunan 410073, People's Republic of China
| | - Chengliang Lin
- Graduate School of China Academy of Engineering Physics, Beijing 100193, People's Republic of China
| | - Yong Hou
- Department of Physics, College of Liberal Arts and Sciences, National University of Defense Technology, Changsha, Hunan 410073, People's Republic of China
| | - Jianmin Yuan
- Department of Physics, College of Liberal Arts and Sciences, National University of Defense Technology, Changsha, Hunan 410073, People's Republic of China.,Graduate School of China Academy of Engineering Physics, Beijing 100193, People's Republic of China
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21
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Zhang P, Jin Y, Zan X, Liu P, Li Y, Gao C, Hou Y, Zeng J, Yuan J. Enhancement of electron-impact ionization induced by warm dense environments. Phys Rev E 2021; 104:035204. [PMID: 34654195 DOI: 10.1103/physreve.104.035204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 08/27/2021] [Indexed: 06/13/2023]
Abstract
Studies have shown significant discrepancies between the recent experiment [Berg et al., Phys. Rev. Lett. 120, 055002 (2018)PRLTAO10.1103/PhysRevLett.120.055002] and current theoretical calculations on the electron-impact ionization cross section of ions in warm dense magnesium. Here, we present a systematic study the effects of the ionic correlations and free-electron screening on the electron-impact ionization of ions in warm dense matter. The ionic correlation and the free-electron screening effects yield additional Hermitian terms to the calculation of the ionic central-force-field potential, which significantly change the electronic structure compared with that of the isolated ion. In calculating the electron-impact ionization, we describe the impact and ionized electrons using a damped-distorted wave function, which considers the momentum relaxation of free electrons due to collisions with other free electrons and ions. We reproduce the electron-impact ionization process for Mg^{7+} in the solid-density plasma and increase the ionization cross section by one order of magnitude compared with that of the isolated ion, which excellently agrees with the experimental result of Berg et al.
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Affiliation(s)
- Ping Zhang
- Department of Physics, College of Liberal Arts and Sciences, National University of Defense Technology, Changsha Hunan 410073, People's Republic of China
| | - Yang Jin
- Department of Physics, College of Liberal Arts and Sciences, National University of Defense Technology, Changsha Hunan 410073, People's Republic of China
| | - Xiaolei Zan
- Department of Physics, College of Liberal Arts and Sciences, National University of Defense Technology, Changsha Hunan 410073, People's Republic of China
| | - Pengfei Liu
- College of Advanced Interdisciplinary Studies, National University of Defense Technology, Changsha Hunan 410073, People's Republic of China
| | - Yongjun Li
- Department of Physics, College of Liberal Arts and Sciences, National University of Defense Technology, Changsha Hunan 410073, People's Republic of China
| | - Cheng Gao
- Department of Physics, College of Liberal Arts and Sciences, National University of Defense Technology, Changsha Hunan 410073, People's Republic of China
| | - Yong Hou
- Department of Physics, College of Liberal Arts and Sciences, National University of Defense Technology, Changsha Hunan 410073, People's Republic of China
| | - Jiaolong Zeng
- Department of Physics, College of Liberal Arts and Sciences, National University of Defense Technology, Changsha Hunan 410073, People's Republic of China
- College of Science, Zhejiang University of Technology, Hangzhou Zhejiang 310023, People's Republic of China
| | - Jianmin Yuan
- Department of Physics, College of Liberal Arts and Sciences, National University of Defense Technology, Changsha Hunan 410073, People's Republic of China
- Graduate School, China Academy of Engineering Physics, Beijing 100193, People's Republic of China
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22
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Baggott RA, Rose SJ, Mangles SPD. Temperature Equilibration due to Charge State Fluctuations in Dense Plasmas. PHYSICAL REVIEW LETTERS 2021; 127:035002. [PMID: 34328772 DOI: 10.1103/physrevlett.127.035002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 05/11/2021] [Accepted: 06/07/2021] [Indexed: 06/13/2023]
Abstract
The charge states of ions in dense plasmas fluctuate due to collisional ionization and recombination. Here, we show how, by modifying the ion interaction potential, these fluctuations can mediate energy exchange between the plasma electrons and ions. Moreover, we develop a theory for this novel electron-ion energy transfer mechanism. Calculations using a random walk approach for the fluctuations suggest that the energy exchange rate from charge state fluctuations could be comparable to direct electron-ion collisions. This mechanism is, however, predicted to exhibit a complex dependence on the temperature and ionization state of the plasma, which could contribute to our understanding of significant variation in experimental measurements of equilibration times.
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Affiliation(s)
- R A Baggott
- Plasma Physics Group, Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom
| | - S J Rose
- Plasma Physics Group, Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom
| | - S P D Mangles
- Plasma Physics Group, Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom
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23
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Dzierżęga K, Sobczuk F, Stambulchik E, Pokrzywka B. Studies of spectral line merging in a laser-induced hydrogen plasma diagnosed with two-color Thomson scattering. Phys Rev E 2021; 103:063207. [PMID: 34271701 DOI: 10.1103/physreve.103.063207] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Accepted: 05/19/2021] [Indexed: 11/07/2022]
Abstract
Laser-induced hydrogen plasma in the density and temperature range of (0.1-5)×10^{23}m^{-3} and (6000-20000)K, respectively, was precisely diagnosed using two-color Thomson scattering technique, inferring the electron number density, electron temperature as well as ion temperature. Simultaneously, spectra of the Balmer series of spectral lines from H-β to H-ζ were measured and plasma emission coefficient calculated within the quasicontiguous frequency-fluctuation model. The theoretical spectra are found to be in good agreement with experimental ones, including higher-density data where discrete lines were observed to merge forming a continuum.
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Affiliation(s)
- Krzysztof Dzierżęga
- Marian Smoluchowski Institute of Physics, Jagiellonian University, ul. Łojasiewicza 11, 30-348 Kraków, Poland
| | | | - Evgeny Stambulchik
- Faculty of Physics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Bartłomiej Pokrzywka
- Institute of Physics, Pedagogical University, ul. Podchoraążych 2, 30-084 Kraków, Poland
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24
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Karasiev VV, Hu SX. Unraveling the intrinsic atomic physics behind x-ray absorption line shifts in warm dense silicon plasmas. Phys Rev E 2021; 103:033202. [PMID: 33862735 DOI: 10.1103/physreve.103.033202] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 02/12/2021] [Indexed: 11/07/2022]
Abstract
We present a free-energy density functional theory (DFT)-based methodology for optical property calculations of warm dense matter to cover a wide range of thermodynamic conditions and photon energies including the entire x-ray range. It uses Mermin-Kohn-Sham density functional theory with exchange-correlation (XC) thermal effects taken into account via a fully temperature dependent generalized gradient approximation XC functional. The methodology incorporates a combination of the ab initio molecular dynamics (AIMD) snapshotted Kubo-Greenwood optic data with a single atom in simulation cell calculations to close the photon energy gap between the L and K edges and extend the K-edge tail toward many-keV photon energies. This gap arises in the standard scheme due to a prohibitively large number of bands required for the Kubo-Greenwood calculations with AIMD snapshots. Kubo-Greenwood data on snapshots provide an accurate description of optic properties at low photon frequencies slightly beyond the L edge and x-ray absorption near edges structure (XANES) spectra, while data from periodic calculations with single atoms cover the tail regions beyond the edges. To demonstrate its applicability to mid-Z materials where the standard DFT-based approach is not computationally feasible, we have applied it to opacity calculations of warm dense silicon plasmas. These first-principles calculations revealed a very interesting phenomenon of redshift-to-blueshift in K-L (1s→2p) and K-edge absorptions along both isotherm and isochore, which are absent in most continuum-lowering models of traditional plasma physics. This new physics phenomenon can be attributed to the underlying competition between the screening of deeply bound core electrons and the screening of outer-shell electrons caused by warm-dense-plasma conditions. We further demonstrate that the ratio of 1s→2p to the K-edge x-ray absorptions can be used to characterize warm-dense-plasma conditions. Eventually, based on our absorption calculations, we have established a first-principles opacity table (FPOT) for silicon in a wide range of material densities and temperatures.
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Affiliation(s)
- Valentin V Karasiev
- Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623 USA
| | - S X Hu
- Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623 USA
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25
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Zhang H, Zhang S, Kang D, Dai J, Bonitz M. Finite-temperature density-functional-theory investigation on the nonequilibrium transient warm-dense-matter state created by laser excitation. Phys Rev E 2021; 103:013210. [PMID: 33601505 DOI: 10.1103/physreve.103.013210] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Accepted: 12/24/2020] [Indexed: 11/07/2022]
Abstract
We present a finite-temperature density-functional-theory investigation of the nonequilibrium transient electronic structure of warm dense Li, Al, Cu, and Au created by laser excitation. Photons excite electrons either from the inner shell orbitals or from the valence bands according to the photon energy, and give rise to isochoric heating of the sample. Localized states related to the 3d orbital are observed for Cu when the hole lies in the inner shell 3s orbital. The electrical conductivity for these materials at nonequilibrium states is calculated using the Kubo-Greenwood formula. The change of the electrical conductivity, compared to the equilibrium state, is different for the case of holes in inner shell orbitals or the valence band. This is attributed to the competition of two factors: the shift of the orbital energies due to reduced screening of core electrons, and the increase of chemical potential due to the excitation of electrons. The finite-temperature effect of both the electrons and the ions on the electrical conductivity is discussed in detail. This work is helpful to better understand the physics of laser excitation experiments of warm dense matter.
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Affiliation(s)
- Hengyu Zhang
- Department of Physics, National University of Defense Technology, Changsha, Hunan 410073, China
| | - Shen Zhang
- Department of Physics, National University of Defense Technology, Changsha, Hunan 410073, China.,Institut für Theoretische Physik und Astrophysik, Christian-Albrechts-Universität zu Kiel, Leibnizstraße 15, 24098 Kiel, Germany
| | - Dongdong Kang
- Department of Physics, National University of Defense Technology, Changsha, Hunan 410073, China
| | - Jiayu Dai
- Department of Physics, National University of Defense Technology, Changsha, Hunan 410073, China
| | - M Bonitz
- Institut für Theoretische Physik und Astrophysik, Christian-Albrechts-Universität zu Kiel, Leibnizstraße 15, 24098 Kiel, Germany
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26
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Jin R, Abdullah MM, Jurek Z, Santra R, Son SK. Transient ionization potential depression in nonthermal dense plasmas at high x-ray intensity. Phys Rev E 2021; 103:023203. [PMID: 33735970 DOI: 10.1103/physreve.103.023203] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 01/22/2021] [Indexed: 11/07/2022]
Abstract
The advent of x-ray free-electron lasers (XFELs), which provide intense ultrashort x-ray pulses, has brought a new way of creating and analyzing hot and warm dense plasmas in the laboratory. Because of the ultrashort pulse duration, the XFEL-produced plasma will be out of equilibrium at the beginning, and even the electronic subsystem may not reach thermal equilibrium while interacting with a femtosecond timescale pulse. In the dense plasma, the ionization potential depression (IPD) induced by the plasma environment plays a crucial role for understanding and modeling microscopic dynamical processes. However, all theoretical approaches for IPD have been based on local thermal equilibrium (LTE), and it has been controversial to use LTE IPD models for the nonthermal situation. In this work, we propose a non-LTE (NLTE) approach to calculate the IPD effect by combining a quantum-mechanical electronic-structure calculation and a classical molecular dynamics simulation. This hybrid approach enables us to investigate the time evolution of ionization potentials and IPDs during and after the interaction with XFEL pulses, without the limitation of the LTE assumption. In our NLTE approach, the transient IPD values are presented as distributions evolving with time, which cannot be captured by conventional LTE-based models. The time-integrated ionization potential values are in good agreement with benchmark experimental data on solid-density aluminum plasma and other theoretical predictions based on LTE. The present work is promising to provide critical insights into nonequilibrium dynamics of dense plasma formation and thermalization induced by XFEL pulses.
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Affiliation(s)
- Rui Jin
- Center for Free-Electron Laser Science, DESY, Notkestrasse 85, 22607 Hamburg, Germany.,Department of Physics and Astronomy, Shanghai Jiao Tong University, 200240 Shanghai, China
| | | | - Zoltan Jurek
- Center for Free-Electron Laser Science, DESY, Notkestrasse 85, 22607 Hamburg, Germany.,The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Robin Santra
- Center for Free-Electron Laser Science, DESY, Notkestrasse 85, 22607 Hamburg, Germany.,The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany.,Department of Physics, Universität Hamburg, Jungiusstrasse 9, 20355 Hamburg, Germany
| | - Sang-Kil Son
- Center for Free-Electron Laser Science, DESY, Notkestrasse 85, 22607 Hamburg, Germany.,The Hamburg Centre for Ultrafast Imaging, Luruper Chaussee 149, 22761 Hamburg, Germany
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27
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Williams GO, Fajardo M. Collisional ionization and recombination in degenerate plasmas beyond the free-electron-gas approximation. Phys Rev E 2021; 102:063204. [PMID: 33466048 DOI: 10.1103/physreve.102.063204] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2020] [Accepted: 11/15/2020] [Indexed: 11/07/2022]
Abstract
One of the most successful ways to model the multitude of electron and photon processes in plasmas is the approach used in collisional radiative (CR) codes. The accuracy of CR codes depends largely on the accuracy of the rates of each process. These rates are generally well approximated in hot, classical plasmas. However, in degenerate plasmas quantum effects can influence these rates and must be accounted for. Previous approaches have developed corrections to the classical rates using the free-electron-gas (FEG) approximation. Here, we use electronic structures beyond the FEG approximation and show how the collisional rates are affected by degeneracy in aluminum and iron plasmas. We find that the FEG is a good approximation for aluminum, whereas more complex electronic structures that include d orbitals, such as iron, deviate from the FEG approximation. This results in different degeneracy corrections to the collisional rates relative to those for the FEG. Although the general trend of the corrections to degenerate plasmas is captured by assuming an FEG, we show that more complex electronic structures can result in deviations, even outside the degenerate regime. This study further advances the treatment of free-electron quantum effects in collisional radiative models.
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Affiliation(s)
- G O Williams
- GoLP/Instituto de Plasmas e Fusão Nuclear-Laboratório Associado, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal
| | - M Fajardo
- GoLP/Instituto de Plasmas e Fusão Nuclear-Laboratório Associado, Instituto Superior Técnico, Universidade de Lisboa, 1049-001 Lisboa, Portugal
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28
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Humphries OS, Marjoribanks RS, van den Berg QY, Galtier EC, Kasim MF, Lee HJ, Miscampbell AJF, Nagler B, Royle R, Wark JS, Vinko SM. Probing the Electronic Structure of Warm Dense Nickel via Resonant Inelastic X-Ray Scattering. PHYSICAL REVIEW LETTERS 2020; 125:195001. [PMID: 33216608 DOI: 10.1103/physrevlett.125.195001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 09/25/2020] [Accepted: 10/07/2020] [Indexed: 06/11/2023]
Abstract
The development of bright free-electron lasers (FEL) has revolutionized our ability to create and study matter in the high-energy-density (HED) regime. Current diagnostic techniques have been successful in yielding information on fundamental thermodynamic plasma properties, but provide only limited or indirect information on the detailed quantum structure of these systems, and on how it is affected by ionization dynamics. Here we show how the valence electronic structure of solid-density nickel, heated to temperatures of around 10 of eV on femtosecond timescales, can be probed by single-shot resonant inelastic x-ray scattering (RIXS) at the Linac Coherent Light Source FEL. The RIXS spectrum provides a wealth of information on the HED system that goes well beyond what can be extracted from x-ray absorption or emission spectroscopy alone, and is particularly well suited to time-resolved studies of electronic-structure dynamics.
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Affiliation(s)
- O S Humphries
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - R S Marjoribanks
- Department of Physics, University of Toronto, 60 St. George Street, Toronto, Ontario M5S 1A7, Canada
| | - Q Y van den Berg
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - E C Galtier
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - M F Kasim
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - H J Lee
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - A J F Miscampbell
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - B Nagler
- Linac Coherent Light Source, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - R Royle
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - J S Wark
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - S M Vinko
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
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29
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Lyu C, Cavaletto SM, Keitel CH, Harman Z. Narrow-band hard-x-ray lasing with highly charged ions. Sci Rep 2020; 10:9439. [PMID: 32523007 PMCID: PMC7287111 DOI: 10.1038/s41598-020-65477-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 05/01/2020] [Indexed: 11/22/2022] Open
Abstract
A scheme is put forward to generate fully coherent x-ray lasers based on population inversion in highly charged ions, created by fast inner-shell photoionization using broadband x-ray free-electron-laser (XFEL) pulses in a laser-produced plasma. Numerical simulations based on the Maxwell–Bloch theory show that one can obtain high-intensity, femtosecond x-ray pulses of relative bandwidths Δω/ω = 10−5–10−7, by orders of magnitude narrower than in x-ray free-electron-laser pulses for discrete wavelengths down to the sub-ångström regime. Such x-ray lasers can be applicable in the study of x-ray quantum optics and metrology, investigating nonlinear interactions between x-rays and matter, or in high-precision spectroscopy studies in laboratory astrophysics.
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Affiliation(s)
- Chunhai Lyu
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117, Heidelberg, Germany
| | - Stefano M Cavaletto
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117, Heidelberg, Germany.
| | - Christoph H Keitel
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117, Heidelberg, Germany
| | - Zoltán Harman
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117, Heidelberg, Germany
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30
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Interspecies radiative transition in warm and superdense plasma mixtures. Nat Commun 2020; 11:1989. [PMID: 32332785 PMCID: PMC7181684 DOI: 10.1038/s41467-020-15916-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Accepted: 04/03/2020] [Indexed: 11/17/2022] Open
Abstract
Superdense plasmas widely exist in planetary interiors and astrophysical objects such as brown-dwarf cores and white dwarfs. How atoms behave under such extreme-density conditions is not yet well understood, even in single-species plasmas. Here, we apply thermal density functional theory to investigate the radiation spectra of superdense iron–zinc plasma mixtures at mass densities of ρ = 250 to 2000 g cm−3 and temperatures of kT = 50 to 100 eV, accessible by double-shell–target implosions. Our ab initio calculations reveal two extreme atomic-physics phenomena—firstly, an interspecies radiative transition; and, secondly, the breaking down of the dipole-selection rule for radiative transitions in isolated atoms. Our first-principles calculations predict that for superdense plasma mixtures, both interatomic radiative transitions and dipole-forbidden transitions can become comparable to the normal intra-atomic Kα-emission signal. These physics phenomena were not previously considered in detail for extreme high-density plasma mixtures at super-high energy densities. Matter at extremely high density and pressure behaves differently than at ambient conditions. Here the authors use first-principles calculations to show the existence of interspecies radiative and dipole-forbidden transitions in warm and superdense plasma mixture of iron and zinc.
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31
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Jiang S, Lazicki AE, Hansen SB, Sterne PA, Grabowski P, Shepherd R, Scott HA, Smith RF, Eggert JH, Ping Y. Measurements of pressure-induced Kβ line shifts in ramp compressed cobalt up to 8 Mbar. Phys Rev E 2020; 101:023204. [PMID: 32168658 DOI: 10.1103/physreve.101.023204] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Accepted: 12/17/2019] [Indexed: 11/07/2022]
Abstract
We report measurements of K-shell fluorescence lines induced by fast electrons in ramp-compressed Co targets. The fluorescence emission was stimulated by fast electrons generated through short-pulse laser-solid interaction with an Al target layer. Compression up to 2.1× solid density was achieved while maintaining temperatures well below the Fermi energy, effectively removing the thermal effects from consideration. We observed small but unambiguous redshifts in the Kβ fluorescence line relative to unshifted Cu Kα. Redshifts up to 2.6 eV were found to increase with compression and to be consistent with predictions from self-consistent models based on density-functional theory.
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Affiliation(s)
- S Jiang
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - A E Lazicki
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - S B Hansen
- Sandia National Laboratory, Albuquerque, New Mexico 87185, USA
| | - P A Sterne
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - P Grabowski
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - R Shepherd
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - H A Scott
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - R F Smith
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - J H Eggert
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - Y Ping
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
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32
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Multispectroscopic Study of Single Xe Clusters Using XFEL Pulses. APPLIED SCIENCES-BASEL 2019. [DOI: 10.3390/app9224932] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
X-ray free-electron lasers (XFELs) deliver ultrashort coherent laser pulses in the X-ray spectral regime, enabling novel investigations into the structure of individual nanoscale samples. In this work, we demonstrate how single-shot small-angle X-ray scattering (SAXS) measurements combined with fluorescence and ion time-of-flight (TOF) spectroscopy can be used to obtain size- and structure-selective evaluation of the light-matter interaction processes on the nanoscale. We recorded the SAXS images of single xenon clusters using XFEL pulses provided by the SPring-8 Angstrom compact free-electron laser (SACLA). The XFEL fluences and the radii of the clusters at the reaction point were evaluated and the ion TOF spectra and fluorescence spectra were sorted accordingly. We found that the XFEL fluence and cluster size extracted from the diffraction patterns showed a clear correlation with the fluorescence and ion TOF spectra. Our results demonstrate the effectiveness of the multispectroscopic approach for exploring laser–matter interaction in the X-ray regime without the influence of the size distribution of samples and the fluence distribution of the incident XFEL pulses.
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33
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X-ray Spectroscopies of High Energy Density Matter Created with X-ray Free Electron Lasers. APPLIED SCIENCES-BASEL 2019. [DOI: 10.3390/app9224812] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The recent progress in the development of X-ray free electron lasers (XFELs) allows for the delivery of over 1011 high-energy photons to solid-density samples in a femtosecond time scale. The corresponding peak brightness of XFEL induces a nonlinear response of matter in a short-wavelength regime. The absorption of an XFEL pulse in a solid also results in the creation of high energy density (HED) matter. The electronic structure and related fundamental properties of such HED matter can be investigated with the control of XFEL and various X-ray spectroscopic techniques. These experimental data provide unique opportunities to benchmark theories and models for extreme conditions and to guide further advances. In this article, the current progress in spectroscopic studies on intense XFEL–matter interactions and HED matter are reviewed, and future research opportunities are discussed.
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34
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Chen ZB. Calculation of the energies and oscillator strengths of Cl 15+ in hot dense plasmas. JOURNAL OF QUANTITATIVE SPECTROSCOPY AND RADIATIVE TRANSFER 2019; 237:106615. [DOI: 10.1016/j.jqsrt.2019.106615] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/01/2023]
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35
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Röpke G, Blaschke D, Döppner T, Lin C, Kraeft WD, Redmer R, Reinholz H. Ionization potential depression and Pauli blocking in degenerate plasmas at extreme densities. Phys Rev E 2019; 99:033201. [PMID: 30999524 DOI: 10.1103/physreve.99.033201] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Indexed: 06/09/2023]
Abstract
New facilities explore warm dense matter (WDM) at conditions with extreme densities (exceeding ten times condensed matter densities) so that electrons are degenerate even at temperatures of 10-100 eV. Whereas in the nondegenerate region correlation effects such as Debye screening are relevant for the ionization potential depression (IPD), new effects have to be considered in degenerate plasmas. In addition to the Fock shift of the self-energies, the bound-state Pauli blocking becomes important with increasing density. Standard approaches to IPD such as Stewart-Pyatt and widely used opacity tables (e.g., OPAL) do not contain Pauli blocking effects for bound states. The consideration of degeneracy effects leads to a reduction of the ionization potential and to a higher degree of ionization. As an example, we present calculations for the ionization degree of carbon plasmas at T = 100 eV and extreme densities up to 40 g/cm^{3}, which are relevant to experiments that are currently scheduled at the National Ignition Facility.
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Affiliation(s)
- Gerd Röpke
- Institut für Physik, Universität Rostock, D-18051 Rostock, Germany
- Department of Theoretical Nuclear Physics, National Research Nuclear University (MEPhI), 115409 Moscow, Russia
| | - David Blaschke
- Department of Theoretical Nuclear Physics, National Research Nuclear University (MEPhI), 115409 Moscow, Russia
- Institute of Theoretical Physics, University of Wroclaw, 50-204 Wroclaw, Poland
- Joint Institute for Nuclear Research, 141980 Dubna, Russia
| | - Tilo Döppner
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - Chengliang Lin
- Institut für Physik, Universität Rostock, D-18051 Rostock, Germany
| | | | - Ronald Redmer
- Institut für Physik, Universität Rostock, D-18051 Rostock, Germany
| | - Heidi Reinholz
- Institut für Physik, Universität Rostock, D-18051 Rostock, Germany
- School of Physics, University of Western Australia, WA 6009 Crawley, Australia
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36
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Gunst J, Wu Y, Keitel CH, Pálffy A. Nuclear excitation by electron capture in optical-laser-generated plasmas. Phys Rev E 2018; 97:063205. [PMID: 30011546 DOI: 10.1103/physreve.97.063205] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Indexed: 11/06/2022]
Abstract
The process of nuclear excitation by electron capture in plasma environments generated by the interaction of ultrastrong optical lasers with solid-state samples is investigated theoretically. With the help of a plasma model, we perform a comprehensive study of the optimal parameters for the most efficient nuclear excitation and determine the corresponding laser setup requirements. We discern between the low-density plasma regime, modeled by scaling laws, and the high-density regime, for which we perform particle-in-cell calculations. As a nuclear transition case study we consider the 4.85-keV nuclear excitation starting from the long-lived ^{93m}Mo isomer. Our results show that the optimal plasma and laser parameters are sensitive to the chosen observable and that measurable rates of nuclear excitation and isomer depletion of ^{93m}Mo should be already achievable at laser facilities existing today.
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Affiliation(s)
- Jonas Gunst
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - Yuanbin Wu
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - Christoph H Keitel
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
| | - Adriana Pálffy
- Max-Planck-Institut für Kernphysik, Saupfercheckweg 1, 69117 Heidelberg, Germany
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37
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Döppner T, Swift DC, Kritcher AL, Bachmann B, Collins GW, Chapman DA, Hawreliak J, Kraus D, Nilsen J, Rothman S, Benedict LX, Dewald E, Fratanduono DE, Gaffney JA, Glenzer SH, Hamel S, Landen OL, Lee HJ, LePape S, Ma T, MacDonald MJ, MacPhee AG, Milathianaki D, Millot M, Neumayer P, Sterne PA, Tommasini R, Falcone RW. Absolute Equation-of-State Measurement for Polystyrene from 25 to 60 Mbar Using a Spherically Converging Shock Wave. PHYSICAL REVIEW LETTERS 2018; 121:025001. [PMID: 30085737 DOI: 10.1103/physrevlett.121.025001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 05/01/2018] [Indexed: 06/08/2023]
Abstract
We have developed an experimental platform for the National Ignition Facility that uses spherically converging shock waves for absolute equation-of-state (EOS) measurements along the principal Hugoniot. In this Letter, we present one indirect-drive implosion experiment with a polystyrene sample that employs radiographic compression measurements over a range of shock pressures reaching up to 60 Mbar (6 TPa). This significantly exceeds previously published results obtained on the Nova laser [R. Cauble et al., Phys. Rev. Lett. 80, 1248 (1998)PRLTAO0031-900710.1103/PhysRevLett.80.1248] at a strongly improved precision, allowing us to discriminate between different EOS models. We find excellent agreement with Kohn-Sham density-functional-theory-based molecular dynamics simulations.
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Affiliation(s)
- T Döppner
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - D C Swift
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - A L Kritcher
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - B Bachmann
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - G W Collins
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
- Department of Mechanical Engineering, Physics and Astronomy, University of Rochester, Rochester, New York 14623, USA
| | - D A Chapman
- AWE plc, Aldermaston RG7 4PR, United Kingdom
| | - J Hawreliak
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - D Kraus
- University of California, Berkeley, California 94720, USA
- Helmholtz-Zentrum Dresden-Rossendorf, 01328 Dresden, Germany
| | - J Nilsen
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - S Rothman
- AWE plc, Aldermaston RG7 4PR, United Kingdom
| | - L X Benedict
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - E Dewald
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - D E Fratanduono
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - J A Gaffney
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - S H Glenzer
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - S Hamel
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - O L Landen
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - H J Lee
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - S LePape
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - T Ma
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - M J MacDonald
- University of California, Berkeley, California 94720, USA
| | - A G MacPhee
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - D Milathianaki
- SLAC National Accelerator Laboratory, Menlo Park, California 94025, USA
| | - M Millot
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - P Neumayer
- GSI Helmholtz-Zentrum für Schwerionenforschung, 64291 Darmstadt, Germany
| | - P A Sterne
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - R Tommasini
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - R W Falcone
- University of California, Berkeley, California 94720, USA
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38
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Driver KP, Soubiran F, Militzer B. Path integral Monte Carlo simulations of warm dense aluminum. Phys Rev E 2018; 97:063207. [PMID: 30011453 DOI: 10.1103/physreve.97.063207] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Indexed: 06/08/2023]
Abstract
We perform first-principles path integral Monte Carlo (PIMC) and density functional theory molecular dynamics (DFT-MD) calculations to explore warm dense matter states of aluminum. Our equation of state (EOS) simulations cover a wide density-temperature range of 0.1-32.4gcm^{-3} and 10^{4}-10^{8} K. Since PIMC and DFT-MD accurately treat effects of the atomic shell structure, we find two compression maxima along the principal Hugoniot curve attributed to K-shell and L-shell ionization. The results provide a benchmark for widely used EOS tables, such as SESAME, QEOS, and models based on Thomas-Fermi and average-atom techniques. A subsequent multishock analysis provides a quantitative assessment for how much heating occurs relative to an isentrope in multishock experiments. Finally, we compute heat capacity, pair-correlation functions, the electronic density of states, and 〈Z〉 to reveal the evolution of the plasma structure and ionization behavior.
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Affiliation(s)
- K P Driver
- Department of Earth and Planetary Science, University of California, Berkeley, California 94720, USA
| | - F Soubiran
- Department of Earth and Planetary Science, University of California, Berkeley, California 94720, USA
| | - B Militzer
- Department of Earth and Planetary Science, University of California, Berkeley, California 94720, USA
- Department of Astronomy, University of California, Berkeley, California 94720, USA
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39
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Validating Continuum Lowering Models via Multi-Wavelength Measurements of Integrated X-ray Emission. Sci Rep 2018; 8:6276. [PMID: 29674688 PMCID: PMC5908972 DOI: 10.1038/s41598-018-24410-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 03/26/2018] [Indexed: 11/11/2022] Open
Abstract
X-ray emission spectroscopy is a well-established technique used to study continuum lowering in dense plasmas. It relies on accurate atomic physics models to robustly reproduce high-resolution emission spectra, and depends on our ability to identify spectroscopic signatures such as emission lines or ionization edges of individual charge states within the plasma. Here we describe a method that forgoes these requirements, enabling the validation of different continuum lowering models based solely on the total intensity of plasma emission in systems driven by narrow-bandwidth x-ray pulses across a range of wavelengths. The method is tested on published Al spectroscopy data and applied to the new case of solid-density partially-ionized Fe plasmas, where extracting ionization edges directly is precluded by the significant overlap of emission from a wide range of charge states.
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40
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van den Berg QY, Fernandez-Tello EV, Burian T, Chalupský J, Chung HK, Ciricosta O, Dakovski GL, Hájková V, Hollebon P, Juha L, Krzywinski J, Lee RW, Minitti MP, Preston TR, de la Varga AG, Vozda V, Zastrau U, Wark JS, Velarde P, Vinko SM. Clocking Femtosecond Collisional Dynamics via Resonant X-Ray Spectroscopy. PHYSICAL REVIEW LETTERS 2018; 120:055002. [PMID: 29481207 DOI: 10.1103/physrevlett.120.055002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Revised: 11/06/2017] [Indexed: 06/08/2023]
Abstract
Electron-ion collisional dynamics is of fundamental importance in determining plasma transport properties, nonequilibrium plasma evolution, and electron damage in diffraction imaging applications using bright x-ray free-electron lasers (FELs). Here we describe the first experimental measurements of ultrafast electron impact collisional ionization dynamics using resonant core-hole spectroscopy in a solid-density magnesium plasma, created and diagnosed with the Linac Coherent Light Source x-ray FEL. By resonantly pumping the 1s→2p transition in highly charged ions within an optically thin plasma, we have measured how off-resonance charge states are populated via collisional processes on femtosecond time scales. We present a collisional cross section model that matches our results and demonstrates how the cross sections are enhanced by dense-plasma effects including continuum lowering. Nonlocal thermodynamic equilibrium collisional radiative simulations show excellent agreement with the experimental results and provide new insight on collisional ionization and three-body-recombination processes in the dense-plasma regime.
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Affiliation(s)
- Q Y van den Berg
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - E V Fernandez-Tello
- Instituto de Fusión Nuclear, Universidad Politécnica de Madrid, José Gutiérrez Abascal 2, 28006 Madrid, Spain
| | - T Burian
- Institute of Physics ASCR, Na Slovance 2, 18221 Prague 8, Czech Republic
- Institute of Plasma Physics CAS, Za Slovankou 3, 182 00 Prague 8, Czech Republic
| | - J Chalupský
- Institute of Physics ASCR, Na Slovance 2, 18221 Prague 8, Czech Republic
| | - H-K Chung
- Atomic and Molecular Data Unit, Nuclear Data Section, IAEA, P.O. Box 100, A-1400 Vienna, Austria
| | - O Ciricosta
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - G L Dakovski
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - V Hájková
- Institute of Physics ASCR, Na Slovance 2, 18221 Prague 8, Czech Republic
| | - P Hollebon
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - L Juha
- Institute of Physics ASCR, Na Slovance 2, 18221 Prague 8, Czech Republic
- Institute of Plasma Physics CAS, Za Slovankou 3, 182 00 Prague 8, Czech Republic
| | - J Krzywinski
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - R W Lee
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - M P Minitti
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - T R Preston
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - A G de la Varga
- Instituto de Fusión Nuclear, Universidad Politécnica de Madrid, José Gutiérrez Abascal 2, 28006 Madrid, Spain
| | - V Vozda
- Institute of Physics ASCR, Na Slovance 2, 18221 Prague 8, Czech Republic
| | - U Zastrau
- European XFEL, Holzkoppel 4, 22869 Schenefeld, Germany
| | - J S Wark
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - P Velarde
- Instituto de Fusión Nuclear, Universidad Politécnica de Madrid, José Gutiérrez Abascal 2, 28006 Madrid, Spain
| | - S M Vinko
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
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41
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Faussurier G, Blancard C. Density effects on electronic configurations in dense plasmas. Phys Rev E 2018; 97:023206. [PMID: 29548182 DOI: 10.1103/physreve.97.023206] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Indexed: 06/08/2023]
Abstract
We present a quantum mechanical model to describe the density effects on electronic configurations inside a plasma environment. Two different approaches are given by starting from a quantum average-atom model. Illustrations are shown for an aluminum plasma in local thermodynamic equilibrium at solid density and at a temperature of 100 eV and in the thermodynamic conditions of a recent experiment designed to characterize the effects of the ionization potential depression treatment. Our approach compares well with experiment and is consistent in that case with the approach of Stewart and Pyatt to describe the ionization potential depression rather than with the method of Ecker and Kröll.
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Affiliation(s)
- Gérald Faussurier
- Commissariat i I'Energie Atomique, DAM, DIF, F-91297 Arpajon, France
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42
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Seddon EA, Clarke JA, Dunning DJ, Masciovecchio C, Milne CJ, Parmigiani F, Rugg D, Spence JCH, Thompson NR, Ueda K, Vinko SM, Wark JS, Wurth W. Short-wavelength free-electron laser sources and science: a review. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2017; 80:115901. [PMID: 29059048 DOI: 10.1088/1361-6633/aa7cca] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
This review is focused on free-electron lasers (FELs) in the hard to soft x-ray regime. The aim is to provide newcomers to the area with insights into: the basic physics of FELs, the qualities of the radiation they produce, the challenges of transmitting that radiation to end users and the diversity of current scientific applications. Initial consideration is given to FEL theory in order to provide the foundation for discussion of FEL output properties and the technical challenges of short-wavelength FELs. This is followed by an overview of existing x-ray FEL facilities, future facilities and FEL frontiers. To provide a context for information in the above sections, a detailed comparison of the photon pulse characteristics of FEL sources with those of other sources of high brightness x-rays is made. A brief summary of FEL beamline design and photon diagnostics then precedes an overview of FEL scientific applications. Recent highlights are covered in sections on structural biology, atomic and molecular physics, photochemistry, non-linear spectroscopy, shock physics, solid density plasmas. A short industrial perspective is also included to emphasise potential in this area.
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Affiliation(s)
- E A Seddon
- ASTeC, STFC Daresbury Laboratory, Sci-Tech Daresbury, Keckwick Lane, Daresbury, Cheshire, WA4 4AD, United Kingdom. The School of Physics and Astronomy and Photon Science Institute, The University of Manchester, Oxford Road, Manchester, M13 9PL, United Kingdom. The Cockcroft Institute, Sci-Tech Daresbury, Keckwick Lane, Daresbury, Cheshire, WA4 4AD, United Kingdom
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43
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Preston TR, Vinko SM, Ciricosta O, Hollebon P, Chung HK, Dakovski GL, Krzywinski J, Minitti M, Burian T, Chalupský J, Hájková V, Juha L, Vozda V, Zastrau U, Lee RW, Wark JS. Measurements of the K-Shell Opacity of a Solid-Density Magnesium Plasma Heated by an X-Ray Free-Electron Laser. PHYSICAL REVIEW LETTERS 2017; 119:085001. [PMID: 28952743 DOI: 10.1103/physrevlett.119.085001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Indexed: 06/07/2023]
Abstract
We present measurements of the spectrally resolved x rays emitted from solid-density magnesium targets of varying sub-μm thicknesses isochorically heated by an x-ray laser. The data exhibit a largely thickness-independent source function, allowing the extraction of a measure of the opacity to K-shell x rays within well-defined regimes of electron density and temperature, extremely close to local thermodynamic equilibrium conditions. The deduced opacities at the peak of the Kα transitions of the ions are consistent with those predicted by detailed atomic-kinetics calculations.
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Affiliation(s)
- T R Preston
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - S M Vinko
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - O Ciricosta
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - P Hollebon
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - H-K Chung
- Atomic and Molecular Data Unit, Nuclear Data Section, IAEA, P.O. Box 100, A-1400 Vienna, Austria
| | - G L Dakovski
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - J Krzywinski
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - M Minitti
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - T Burian
- Institute of Physics ASCR, Na Slovance 2, 18221 Prague 8, Czech Republic
| | - J Chalupský
- Institute of Physics ASCR, Na Slovance 2, 18221 Prague 8, Czech Republic
| | - V Hájková
- Institute of Physics ASCR, Na Slovance 2, 18221 Prague 8, Czech Republic
| | - L Juha
- Institute of Physics ASCR, Na Slovance 2, 18221 Prague 8, Czech Republic
| | - V Vozda
- Institute of Physics ASCR, Na Slovance 2, 18221 Prague 8, Czech Republic
| | - U Zastrau
- European XFEL GmbH, Holzkoppel 4, 22869 Schenefeld, Germany
| | - R W Lee
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - J S Wark
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
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44
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Cho BI, Cho MS, Kim M, Chung HK, Barbrel B, Engelhorn K, Burian T, Chalupský J, Ciricosta O, Dakovski GL, Hájková V, Holmes M, Juha L, Krzywinski J, Lee RW, Nam CH, Rackstraw DS, Toleikis S, Turner JJ, Vinko SM, Wark JS, Zastrau U, Heimann PA. Observation of Reverse Saturable Absorption of an X-ray Laser. PHYSICAL REVIEW LETTERS 2017; 119:075002. [PMID: 28949680 DOI: 10.1103/physrevlett.119.075002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Indexed: 06/07/2023]
Abstract
A nonlinear absorber in which the excited state absorption is larger than the ground state can undergo a process called reverse saturable absorption. It is a well-known phenomenon in laser physics in the optical regime, but is more difficult to generate in the x-ray regime, where fast nonradiative core electron transitions typically dominate the population kinetics during light matter interactions. Here, we report the first observation of decreasing x-ray transmission in a solid target pumped by intense x-ray free electron laser pulses. The measurement has been made below the K-absorption edge of aluminum, and the x-ray intensity ranges are 10^{16} -10^{17} W/cm^{2}. It has been confirmed by collisional radiative population kinetic calculations, underscoring the fast spectral modulation of the x-ray pulses and charge states relevant to the absorption and transmission of x-ray photons. The processes shown through detailed simulations are consistent with reverse saturable absorption, which would be the first observation of this phenomena in the x-ray regime. These light matter interactions provide a unique opportunity to investigate optical transport properties in the extreme state of matters, as well as affording the potential to regulate ultrafast x-ray free-electron laser pulses.
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Affiliation(s)
- B I Cho
- Center for Relativistic Laser Science, Institute for Basic Science (IBS), Gwangju 61005, Korea
- Department of Physics and Photon Science, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
| | - M S Cho
- Center for Relativistic Laser Science, Institute for Basic Science (IBS), Gwangju 61005, Korea
- Department of Physics and Photon Science, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
| | - M Kim
- Center for Relativistic Laser Science, Institute for Basic Science (IBS), Gwangju 61005, Korea
- Department of Physics and Photon Science, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
| | - H-K Chung
- Atomic and Molecular Data Unit, Nuclear Data Section, IAEA, P.O. Box 100, A-1400 Vienna, Austria
| | - B Barbrel
- Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, USA
| | - K Engelhorn
- Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, California 94720, USA
| | - T Burian
- Institute of Physics ASCR, Na Slovance 2, 18221 Prague 8, Czech Republic
| | - J Chalupský
- Institute of Physics ASCR, Na Slovance 2, 18221 Prague 8, Czech Republic
| | - O Ciricosta
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - G L Dakovski
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - V Hájková
- Institute of Physics ASCR, Na Slovance 2, 18221 Prague 8, Czech Republic
| | - M Holmes
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - L Juha
- Institute of Physics ASCR, Na Slovance 2, 18221 Prague 8, Czech Republic
| | - J Krzywinski
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - R W Lee
- Department of Physics, University of California, Berkeley, California 94720, USA
| | - Chang Hee Nam
- Center for Relativistic Laser Science, Institute for Basic Science (IBS), Gwangju 61005, Korea
- Department of Physics and Photon Science, Gwangju Institute of Science and Technology, Gwangju 61005, Korea
| | - D S Rackstraw
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - S Toleikis
- Deutsches-Elektronensynchrotron DESY, Notkestrasse 85, D-22603 Hamburg, Germany
| | - J J Turner
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
| | - S M Vinko
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - J S Wark
- Department of Physics, Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU, United Kingdom
| | - U Zastrau
- European XFEL, Holzkoppel 4, 22869 Schenefeld, Germany
| | - P A Heimann
- SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA
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45
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Hu SX. Continuum Lowering and Fermi-Surface Rising in Strongly Coupled and Degenerate Plasmas. PHYSICAL REVIEW LETTERS 2017; 119:065001. [PMID: 28949647 DOI: 10.1103/physrevlett.119.065001] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Indexed: 06/07/2023]
Abstract
Continuum lowering is a well known and important physics concept that describes the ionization potential depression (IPD) in plasmas caused by thermal- or pressure-induced ionization of outer-shell electrons. The existing IPD models are often used to characterize plasma conditions and to gauge opacity calculations. Recent precision measurements have revealed deficits in our understanding of continuum lowering in dense hot plasmas. However, these investigations have so far been limited to IPD in strongly coupled but nondegenerate plasmas. Here, we report a first-principles study of the K-edge shifting in both strongly coupled and fully degenerate carbon plasmas, with quantum molecular dynamics calculations based on the all-electron density-functional theory. The resulting K-edge shifting versus plasma density, as a probe to the continuum lowering and the Fermi-surface rising, is found to be significantly different from predictions of existing IPD models. In contrast, a simple model of "single-atom-in-box," developed in this work, accurately predicts K-edge locations as ab initio calculations provide.
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Affiliation(s)
- S X Hu
- Laboratory for Laser Energetics, University of Rochester, 250 E. River Road, Rochester, New York 14623, USA
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46
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McKelvey A, Kemp GE, Sterne PA, Fernandez-Panella A, Shepherd R, Marinak M, Link A, Collins GW, Sio H, King J, Freeman RR, Hua R, McGuffey C, Kim J, Beg FN, Ping Y. Thermal conductivity measurements of proton-heated warm dense aluminum. Sci Rep 2017; 7:7015. [PMID: 28765571 PMCID: PMC5539319 DOI: 10.1038/s41598-017-07173-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 06/21/2017] [Indexed: 11/19/2022] Open
Abstract
Thermal conductivity is one of the most crucial physical properties of matter when it comes to understanding heat transport, hydrodynamic evolution, and energy balance in systems ranging from astrophysical objects to fusion plasmas. In the warm dense matter regime, experimental data are very scarce so that many theoretical models remain untested. Here we present the first thermal conductivity measurements of aluminum at 0.5–2.7 g/cc and 2–10 eV, using a recently developed platform of differential heating. A temperature gradient is induced in a Au/Al dual-layer target by proton heating, and subsequent heat flow from the hotter Au to the Al rear surface is detected by two simultaneous time-resolved diagnostics. A systematic data set allows for constraining both thermal conductivity and equation-of-state models. Simulations using Purgatorio model or Sesame S27314 for Al thermal conductivity and LEOS for Au/Al release equation-of-state show good agreement with data after 15 ps. Discrepancy still exists at early time 0–15 ps, likely due to non-equilibrium conditions.
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Affiliation(s)
- A McKelvey
- Lawrence Livermore National Laboratory, Livermore, CA, 94550, USA.,University of Michigan, Nuclear Engineering Department, Ann Arbor, MI, 48109, USA
| | - G E Kemp
- Lawrence Livermore National Laboratory, Livermore, CA, 94550, USA
| | - P A Sterne
- Lawrence Livermore National Laboratory, Livermore, CA, 94550, USA
| | | | - R Shepherd
- Lawrence Livermore National Laboratory, Livermore, CA, 94550, USA
| | - M Marinak
- Lawrence Livermore National Laboratory, Livermore, CA, 94550, USA
| | - A Link
- Lawrence Livermore National Laboratory, Livermore, CA, 94550, USA
| | - G W Collins
- Lawrence Livermore National Laboratory, Livermore, CA, 94550, USA
| | - H Sio
- Massachusetts Institute of Technology, Plasma Science and Fusion Center, Cambridge, MA, 02139, USA
| | - J King
- The Ohio State University, Physics Department, Columbus, Ohio, 43210, USA
| | - R R Freeman
- The Ohio State University, Physics Department, Columbus, Ohio, 43210, USA
| | - R Hua
- University of California San Diego, Center for Energy Research, La Jolla, CA, 92093, USA
| | - C McGuffey
- University of California San Diego, Center for Energy Research, La Jolla, CA, 92093, USA
| | - J Kim
- University of California San Diego, Center for Energy Research, La Jolla, CA, 92093, USA
| | - F N Beg
- University of California San Diego, Center for Energy Research, La Jolla, CA, 92093, USA
| | - Y Ping
- Lawrence Livermore National Laboratory, Livermore, CA, 94550, USA.
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47
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Lin C, Röpke G, Kraeft WD, Reinholz H. Ionization-potential depression and dynamical structure factor in dense plasmas. Phys Rev E 2017; 96:013202. [PMID: 29347154 DOI: 10.1103/physreve.96.013202] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Indexed: 06/07/2023]
Abstract
The properties of a bound electron system immersed in a plasma environment are strongly modified by the surrounding plasma. The modification of an essential quantity, the ionization energy, is described by the electronic and ionic self-energies, including dynamical screening within the framework of the quantum statistical theory. Introducing the ionic dynamical structure factor as the indicator for the ionic microfield, we demonstrate that ionic correlations and fluctuations play a critical role in determining the ionization potential depression. This is, in particular, true for mixtures of different ions with large mass and charge asymmetry. The ionization potential depression is calculated for dense aluminum plasmas as well as for a CH plasma and compared to the experimental data and more phenomenological approaches used so far.
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Affiliation(s)
- Chengliang Lin
- Universität Rostock, Institut für Physik, 18051 Rostock, Germany
| | - Gerd Röpke
- Universität Rostock, Institut für Physik, 18051 Rostock, Germany
| | | | - Heidi Reinholz
- Universität Rostock, Institut für Physik, 18051 Rostock, Germany
- University of Western Australia School of Physics, WA 6009 Crawley, Australia
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48
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Mo MZ, Chen Z, Fourmaux S, Saraf A, Kerr S, Otani K, Masoud R, Kieffer JC, Tsui Y, Ng A, Fedosejevs R. Measurements of ionization states in warm dense aluminum with betatron radiation. Phys Rev E 2017; 95:053208. [PMID: 28618605 DOI: 10.1103/physreve.95.053208] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2017] [Indexed: 11/07/2022]
Abstract
Time-resolved measurements of the ionization states of warm dense aluminum via K-shell absorption spectroscopy are demonstrated using betatron radiation generated from laser wakefield acceleration as a probe. The warm dense aluminum is generated by irradiating a free-standing nanofoil with a femtosecond optical laser pulse and was heated to an electron temperature of ∼20-25 eV at a close-to-solid mass density. Absorption dips in the transmitted x-ray spectrum due to the Al^{4+} and Al^{5+} ions are clearly seen during the experiments. The measured absorption spectra are compared to simulations with various ionization potential depression models, including the commonly used Stewart-Pyatt model and an alternative modified Ecker-Kröll model. The observed absorption spectra are in approximate agreement with these models, though indicating a slightly higher state of ionization and closer agreement for simulations with the modified Ecker-Kröll model.
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Affiliation(s)
- M Z Mo
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta, Canada, T6G 2V4
| | - Z Chen
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta, Canada, T6G 2V4
| | - S Fourmaux
- INRS-EMT, Université du Québec, 1650 Lionel Boulet, Varennes, Quebéc, Canada, J3X 1S2
| | - A Saraf
- INRS-EMT, Université du Québec, 1650 Lionel Boulet, Varennes, Quebéc, Canada, J3X 1S2
| | - S Kerr
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta, Canada, T6G 2V4
| | - K Otani
- INRS-EMT, Université du Québec, 1650 Lionel Boulet, Varennes, Quebéc, Canada, J3X 1S2
| | - R Masoud
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta, Canada, T6G 2V4
| | - J-C Kieffer
- INRS-EMT, Université du Québec, 1650 Lionel Boulet, Varennes, Quebéc, Canada, J3X 1S2
| | - Y Tsui
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta, Canada, T6G 2V4
| | - A Ng
- Department of Physics and Astronomy, University of British Columbia, Vancouver, British Columbia, Canada, V6T 1Z1
| | - R Fedosejevs
- Department of Electrical and Computer Engineering, University of Alberta, Edmonton, Alberta, Canada, T6G 2V4
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49
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Royle R, Sentoku Y, Mancini RC, Paraschiv I, Johzaki T. Kinetic modeling of x-ray laser-driven solid Al plasmas via particle-in-cell simulation. Phys Rev E 2017; 95:063203. [PMID: 28709226 DOI: 10.1103/physreve.95.063203] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Indexed: 06/07/2023]
Abstract
Solid-density plasmas driven by intense x-ray free-electron laser (XFEL) radiation are seeded by sources of nonthermal photoelectrons and Auger electrons that ionize and heat the target via collisions. Simulation codes that are commonly used to model such plasmas, such as collisional-radiative (CR) codes, typically assume a Maxwellian distribution and thus instantaneous thermalization of the source electrons. In this study, we present a detailed description and initial applications of a collisional particle-in-cell code, picls, that has been extended with a self-consistent radiation transport model and Monte Carlo models for photoionization and KLL Auger ionization, enabling the fully kinetic simulation of XFEL-driven plasmas. The code is used to simulate two experiments previously performed at the Linac Coherent Light Source investigating XFEL-driven solid-density Al plasmas. It is shown that picls-simulated pulse transmissions using the Ecker-Kröll continuum-lowering model agree much better with measurements than do simulations using the Stewart-Pyatt model. Good quantitative agreement is also found between the time-dependent picls results and those of analogous simulations by the CR code scfly, which was used in the analysis of the experiments to accurately reproduce the observed Kα emissions and pulse transmissions. Finally, it is shown that the effects of the nonthermal electrons are negligible for the conditions of the particular experiments under investigation.
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Affiliation(s)
- R Royle
- Department of Physics, University of Nevada, Reno, Nevada 89557, USA
| | - Y Sentoku
- Department of Physics, University of Nevada, Reno, Nevada 89557, USA
- Institute of Laser Engineering, Osaka University, Osaka Prefecture 565-0871, Japan
| | - R C Mancini
- Department of Physics, University of Nevada, Reno, Nevada 89557, USA
| | - I Paraschiv
- Voss Scientific, LLC, Albuquerque, New Mexico 87108, USA
| | - T Johzaki
- Graduate School of Engineering, Hiroshima University, Hiroshima Prefecture 739-8527, Japan
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50
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Rana V, Lim H, Melvin J, Glimm J, Cheng B, Sharp DH. Mixing with applications to inertial-confinement-fusion implosions. Phys Rev E 2017; 95:013203. [PMID: 28208418 DOI: 10.1103/physreve.95.013203] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Indexed: 11/07/2022]
Abstract
Approximate one-dimensional (1D) as well as 2D and 3D simulations are playing an important supporting role in the design and analysis of future experiments at National Ignition Facility. This paper is mainly concerned with 1D simulations, used extensively in design and optimization. We couple a 1D buoyancy-drag mix model for the mixing zone edges with a 1D inertial confinement fusion simulation code. This analysis predicts that National Ignition Campaign (NIC) designs are located close to a performance cliff, so modeling errors, design features (fill tube and tent) and additional, unmodeled instabilities could lead to significant levels of mix. The performance cliff we identify is associated with multimode plastic ablator (CH) mix into the hot-spot deuterium and tritium (DT). The buoyancy-drag mix model is mode number independent and selects implicitly a range of maximum growth modes. Our main conclusion is that single effect instabilities are predicted not to lead to hot-spot mix, while combined mode mixing effects are predicted to affect hot-spot thermodynamics and possibly hot-spot mix. Combined with the stagnation Rayleigh-Taylor instability, we find the potential for mix effects in combination with the ice-to-gas DT boundary, numerical effects of Eulerian species CH concentration diffusion, and ablation-driven instabilities. With the help of a convenient package of plasma transport parameters developed here, we give an approximate determination of these quantities in the regime relevant to the NIC experiments, while ruling out a variety of mix possibilities. Plasma transport parameters affect the 1D buoyancy-drag mix model primarily through its phenomenological drag coefficient as well as the 1D hydro model to which the buoyancy-drag equation is coupled.
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Affiliation(s)
- V Rana
- Department of Applied Mathematics and Statistics, Stony Brook University, Stony Brook, New York 11794-3600, USA
| | - H Lim
- Department of Applied Mathematics and Statistics, Stony Brook University, Stony Brook, New York 11794-3600, USA
| | - J Melvin
- Department of Applied Mathematics and Statistics, Stony Brook University, Stony Brook, New York 11794-3600, USA
| | - J Glimm
- Department of Applied Mathematics and Statistics, Stony Brook University, Stony Brook, New York 11794-3600, USA
| | - B Cheng
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - D H Sharp
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
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