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Freeman RR, Batani D, Baton S, Key M, Stephens R. The Generation and Transport of Large Currents in Dense Materials: The Physics of Electron Transport Relative to Fast Ignition. FUSION SCIENCE AND TECHNOLOGY 2017. [DOI: 10.13182/fst06-a1150] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- R. R. Freeman
- The Ohio State University, College of Mathematical and Physical Sciences, Columbus, Ohio 43210-1123 and University of California, Davis, Davis, California 95616
| | - D. Batani
- Università degli Studi di Milano and Istituto Nazionale per la Fisica della Materia (INFM), Dipartimento di Fisica, Milan, Italy
| | - S. Baton
- Ecole Polytechnique, Laboratoire pour l’Utilisation des Lasers Intenses (LULI), Palaiseau, France
| | - M. Key
- Lawrence Livermore National Laboratory, University of California, Livermore, California 94550
| | - R. Stephens
- General Atomics, Inc., San Diego, California 92186
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Le Pape S, Tsui YY, Macphee A, Hey D, Patel P, Mackinnon A, Key M, Wei M, Ma T, Beg FN, Stephens R, Akli K, Link T, Van-Woerkom L, Freeman RR. Characterization of the preformed plasma for high-intensity laser-plasma interaction. OPTICS LETTERS 2009; 34:2997-2999. [PMID: 19794794 DOI: 10.1364/ol.34.002997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The interaction of a very intense, very short laser pulse is modified by the presence of a preformed plasma prior to the main short pulse. The preformed plasma is created by a small prepulse interacting with the target prior to the main pulse. The prepulse has been monitored using a water-cell-protected fast photodiode allowing on every shot a high dynamic measurement of the pulse profile. Simultaneously we have used time-resolved interferometry to look at the preformed plasma on a 300 TW, 700 fs laser. The two-dimensional density maps obtained have been compared with two-dimensional hydrodynamic simulations.
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Affiliation(s)
- Sebastien Le Pape
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA.
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Gerbaux M, Gobet F, Aléonard MM, Hannachi F, Malka G, Scheurer JN, Tarisien M, Claverie G, Méot V, Morel P, Faure J, Glinec Y, Guemnie-Tafo A, Malka V, Manclossi M, Santos JJ. High flux of relativistic electrons produced in femtosecond laser-thin foil target interactions: characterization with nuclear techniques. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2008; 79:023504. [PMID: 18315296 DOI: 10.1063/1.2840017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
We present a protocol to characterize the high energy electron beam emitted in the interaction of an ultraintense laser with matter at intensities higher than 10(19) W cm(-2). The electron energies and angular distributions are determined as well as the total number of electrons produced above a 10 MeV threshold. This protocol is based on measurements with an electron spectrometer and nuclear activation techniques, combined with Monte Carlo simulations based on the GEANT3 code. The method is detailed and exemplified with data obtained with polypropylene and copper thin solid targets at a laser intensity of 2x10(19) W cm(-2). Special care is taken of the different sources of uncertainties. In particular, the reproducibility of the laser shots is considered.
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Affiliation(s)
- M Gerbaux
- Université Bordeaux 1, CNRS-IN2P3, Centre d'Etudes Nucléaires de Bordeaux Gradignan, Chemin du Solarium, 33175 Gradignan, France.
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Fournier KB, Faenov AY, Pikuz TA, Skobelev IY, Belyaev VS, Vinogradov VI, Kyrilov AS, Matafonov AP, Bellucci I, Martellucci S, Petrocelli G, Auguste T, Hulin S, Monot P, D'Oliveira P. Influence of optical thickness and hot electrons on Rydberg spectra of Ne-like and F-like copper ions. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2003; 67:016402. [PMID: 12636606 DOI: 10.1103/physreve.67.016402] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2002] [Indexed: 05/24/2023]
Abstract
Spectra in the 7.10 to 8.60 A range from highly charged copper ions are observed from three different laser-produced plasmas (LPPs). The LPPs are formed by a 15-ns Nd:glass laser pulse (type I: E(pulse)=1-8 J, lambda=1.064 microm), a 1-ps Nd:glass laser pulse (type II: E(pulse)=1 J, lambda=1.055 microm), and a 60-fs Ti:sapphire laser pulse (type III: E(pulse)=800 mJ, lambda=790 nm). The spectra of high-n (n<or=14) transitions in highly charged copper ions, Cu19+ to Cu21+, are recorded with a high energy resolution (lambda/deltalambda=3000-8000) spectrometer using a spherically bent mica or quartz crystal. Collisional-radiative models are computed for the emission from each plasma. The sensitivity of the model spectra to opacity effects and to populations of superthermal electrons is studied. For the type I LPPs, opacity effects, treated with escape factors, are necessary to get the correct relative intensities of high-n (n=5, 6) Ne-like Cu19+ emission features. In the case of the type II LPPs, the contrast between the laser prepulse and the main pulse has been varied from low, I(main)/I(pp)=7 x 10(4), to high, I(main)/I(pp)=3.8 x 10(7). For plasmas from low contrast shots, we find good agreement between the observed spectra and optically thin simulations with bulk electron temperatures T(bulk)=0.4 keV and a small population of superthermal electrons (T(hot)=5.0 keV) that is f(hot)<or=10(-5) of the bulk electron population. For high-contrast type II LPPs, we find higher densities and a combination of f(hot) approximately 10(-5) and escape factors best describes the data. For the type III 60-fs LPPs, a population of superthermal electrons (T(hot) approximately 5 keV) that is approximately 5 x 10(-5) of the bulk electron population (T(bulk) approximately 0.2 keV) is required to reproduce the observed spectra. The effect of both escape factors and hot electrons in the CR models is to increase the ionization balance and dramatically increase the number of strong lines for each ion considered. We have studied both opacity effects and hot-electron influence on high-n transitions of highly charged Ne-, F-, and O-like ions.
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Affiliation(s)
- K B Fournier
- Lawrence Livermore National Laboratory, P. O. Box 808, L-41, Livermore, California 94550, USA
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Malka G, Aleonard MM, Chemin JF, Claverie G, Harston MR, Scheurer JN, Tikhonchuk V, Fritzler S, Malka V, Balcou P, Grillon G, Moustaizis S, Notebaert L, Lefebvre E, Cochet N. Relativistic electron generation in interactions of a 30 TW laser pulse with a thin foil target. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2002; 66:066402. [PMID: 12513407 DOI: 10.1103/physreve.66.066402] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2002] [Indexed: 05/24/2023]
Abstract
Energy and angular distributions of the fast outgoing electron beam induced by the interaction of a 1 J, 30 fs, 2 x 10(19) W/cm(2), 10 Hz laser with a thin foil target are characterized by electron energy spectroscopy and photonuclear reactions. We have investigated the effect of the target thickness and the intensity contrast ratio level on the electron production. Using a 6-microm polyethylene target, up to 4 x 10(8) electrons with energies between 5 and 60 MeV were produced per laser pulse and converted to gamma rays by bremsstrahlung in a Ta secondary target. The rates of photofission of U as well as photonuclear reactions in Cu, Au, and C samples have been measured. In optimal focusing conditions, about 0.06% of the laser energy has been converted to outgoing electrons with energies above 5 MeV. Such electrons leave the target in the laser direction with an opening angle of 2.5 degrees.
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Affiliation(s)
- G Malka
- Centre d'Etudes Nucléaires de Bordeaux-Gradignan, France.
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Pretzler G, Schlegel T, Fill E, Eder D. Hot-electron generation in copper and photopumping of cobalt. PHYSICAL REVIEW. E, STATISTICAL PHYSICS, PLASMAS, FLUIDS, AND RELATED INTERDISCIPLINARY TOPICS 2000; 62:5618-5623. [PMID: 11089120 DOI: 10.1103/physreve.62.5618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2000] [Indexed: 05/23/2023]
Abstract
Hot electrons generated upon interaction of p-polarized 130 fs laser pulses with copper and penetrating into the target material are characterized with respect to their energy distribution and directionality. "Experimental" data are obtained by comparing the rear-side x-ray emission from layered targets with Monte Carlo electron-photon transport simulations. Theoretical electron energy distributions are derived by means of a one and a half-dimensional particle-in-cell code. Both sets of data consist of a two-temperature distribution of electrons propagating in a direction almost perpendicular to the target surface. The "experimental" data contain a considerably higher population of the lower temperature electrons. The discrepancy is explained by the intensity distribution of the laser spot. The results are used to design an experiment for demonstrating photopumping of cobalt with copper Kalpha radiation. A 10 &mgr;m copper foil is backed with 1 mm of polyethylene (PE) followed by 10 &mgr;m of cobalt, the rear-side Kalpha emission of which is measured. The PE layer prevents fast electrons from reaching the cobalt. Comparing the cobalt Kalpha emission with that of nickel, which is not photopumped by copper Kalpha shows enhancement by almost a factor of 2.
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Affiliation(s)
- G Pretzler
- Max-Planck-Institut fur Quantenoptik, D-85748 Garching, Germany
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Batani D, Davies JR, Bernardinello A, Pisani F, Koenig M, Hall TA, Ellwi S, Norreys P, Rose S, Djaoui A, Neely D. Explanations for the observed increase in fast electron penetration in laser shock compressed materials. PHYSICAL REVIEW. E, STATISTICAL PHYSICS, PLASMAS, FLUIDS, AND RELATED INTERDISCIPLINARY TOPICS 2000; 61:5725-5733. [PMID: 11031632 DOI: 10.1103/physreve.61.5725] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/1999] [Indexed: 05/23/2023]
Abstract
We analyze recent experimental results on the increase of fast electron penetration in shock compressed plastic [Phys. Rev. Lett. 81, 1003 (1998)]. It is explained by a combination of stopping power and electric field effects, which appear to be important even at laser intensities as low as 10(16) W cm-2. An important conclusion is that fast electron induced heating must be taken into account, changing the properties of the material in which the fast electrons propagate. In insulators this leads to a rapid insulator to conductor phase transition.
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Affiliation(s)
- D Batani
- Dipartimento di Fisica G. Occhialini, Universita degli Studi di Milano, Bicocca and INFM, Italy
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