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Buldgen G, Salmon SJAJ, Godart M, Noels A, Scuflaire R, Dupret MA, Reese DR, Colgan J, Fontes CJ, Eggenberger P, Hakel P, Kilcrease DP, Richard O. Inversions of the Ledoux discriminant: a closer look at the tachocline. ACTA ACUST UNITED AC 2017. [DOI: 10.1093/mnrasl/slx139] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Shah RC, Haines BM, Wysocki FJ, Benage JF, Fooks JA, Glebov V, Hakel P, Hoppe M, Igumenshchev IV, Kagan G, Mancini RC, Marshall FJ, Michel DT, Murphy TJ, Schoff ME, Silverstein K, Stoeckl C, Yaakobi B. Systematic Fuel Cavity Asymmetries in Directly Driven Inertial Confinement Fusion Implosions. Phys Rev Lett 2017; 118:135001. [PMID: 28409959 DOI: 10.1103/physrevlett.118.135001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Indexed: 06/07/2023]
Abstract
We present narrow-band self-emission x-ray images from a titanium tracer layer placed at the fuel-shell interface in 60-laser-beam implosion experiments at the OMEGA facility. The images are acquired during deceleration with inferred convergences of ∼9-14. Novel here is that a systematically observed asymmetry of the emission is linked, using full sphere 3D implosion modeling, to performance-limiting low mode asymmetry of the drive.
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Affiliation(s)
- R C Shah
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - B M Haines
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - F J Wysocki
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - J F Benage
- Sandia National Laboratories, Albuquerque, New Mexico 87123, USA
| | - J A Fooks
- General Atomics, San Diego, California 92121, USA
| | - V Glebov
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - P Hakel
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - M Hoppe
- General Atomics, San Diego, California 92121, USA
| | - I V Igumenshchev
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - G Kagan
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - R C Mancini
- Department of Physics, University of Nevada, Reno, Nevada 89557, USA
| | - F J Marshall
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - D T Michel
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - T J Murphy
- Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - M E Schoff
- General Atomics, San Diego, California 92121, USA
| | - K Silverstein
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - C Stoeckl
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
| | - B Yaakobi
- Laboratory for Laser Energetics, University of Rochester, Rochester, New York 14623, USA
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Booth N, Robinson APL, Hakel P, Clarke RJ, Dance RJ, Doria D, Gizzi LA, Gregori G, Koester P, Labate L, Levato T, Li B, Makita M, Mancini RC, Pasley J, Rajeev PP, Riley D, Wagenaars E, Waugh JN, Woolsey NC. Laboratory measurements of resistivity in warm dense plasmas relevant to the microphysics of brown dwarfs. Nat Commun 2015; 6:8742. [PMID: 26541650 PMCID: PMC4667641 DOI: 10.1038/ncomms9742] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 09/28/2015] [Indexed: 11/09/2022] Open
Abstract
Since the observation of the first brown dwarf in 1995, numerous studies have led to a better understanding of the structures of these objects. Here we present a method for studying material resistivity in warm dense plasmas in the laboratory, which we relate to the microphysics of brown dwarfs through viscosity and electron collisions. Here we use X-ray polarimetry to determine the resistivity of a sulphur-doped plastic target heated to Brown Dwarf conditions by an ultra-intense laser. The resistivity is determined by matching the plasma physics model to the atomic physics calculations of the measured large, positive, polarization. The inferred resistivity is larger than predicted using standard resistivity models, suggesting that these commonly used models will not adequately describe the resistivity of warm dense plasma related to the viscosity of brown dwarfs.
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Affiliation(s)
- N Booth
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Didcot OX11 0QX, UK
| | - A P L Robinson
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Didcot OX11 0QX, UK
| | - P Hakel
- Department of Physics, College of Science, University of Nevada, Reno, Nevada 89557-0208, USA
| | - R J Clarke
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Didcot OX11 0QX, UK
| | - R J Dance
- Department of Physics, York Plasma Institute, University of York, Heslington York YO10 5DD, UK
| | - D Doria
- School of Mathematics and Physics, Queen's University Belfast, Belfast BT1 4NN, UK
| | - L A Gizzi
- Intense Laser Irradiation Laboratory, Istituto Nazionale di Ottica, Area della Ricerca del CNR, 56124 Pisa, Italy
| | - G Gregori
- Department of Physics, University of Oxford, Oxford OX4 3PU, UK
| | - P Koester
- Intense Laser Irradiation Laboratory, Istituto Nazionale di Ottica, Area della Ricerca del CNR, 56124 Pisa, Italy
| | - L Labate
- Intense Laser Irradiation Laboratory, Istituto Nazionale di Ottica, Area della Ricerca del CNR, 56124 Pisa, Italy
| | - T Levato
- Intense Laser Irradiation Laboratory, Istituto Nazionale di Ottica, Area della Ricerca del CNR, 56124 Pisa, Italy
| | - B Li
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Didcot OX11 0QX, UK
| | - M Makita
- School of Mathematics and Physics, Queen's University Belfast, Belfast BT1 4NN, UK
| | - R C Mancini
- Department of Physics, College of Science, University of Nevada, Reno, Nevada 89557-0208, USA
| | - J Pasley
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Didcot OX11 0QX, UK.,Department of Physics, York Plasma Institute, University of York, Heslington York YO10 5DD, UK
| | - P P Rajeev
- Central Laser Facility, STFC Rutherford Appleton Laboratory, Didcot OX11 0QX, UK
| | - D Riley
- School of Mathematics and Physics, Queen's University Belfast, Belfast BT1 4NN, UK
| | - E Wagenaars
- Department of Physics, York Plasma Institute, University of York, Heslington York YO10 5DD, UK
| | - J N Waugh
- Department of Physics, York Plasma Institute, University of York, Heslington York YO10 5DD, UK
| | - N C Woolsey
- Department of Physics, York Plasma Institute, University of York, Heslington York YO10 5DD, UK
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Ivanov VV, Chittenden JP, Altemara SD, Niasse N, Hakel P, Mancini RC, Papp D, Anderson AA. Study of the internal structure and small-scale instabilities in the dense Z pinch. Phys Rev Lett 2011; 107:165002. [PMID: 22107394 DOI: 10.1103/physrevlett.107.165002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2011] [Indexed: 05/31/2023]
Abstract
High-resolution laser diagnostics at the wavelength of 266 nm were applied for the investigation of Z pinches at the 1-MA generator. The internal structure of the stagnated Z pinches was observed in unprecedented detail. A dense pinch with strong instabilities was seen inside the column of the trailing plasma. Kink instability, disruptions, and micropinches were seen at the peak of the x-ray pulse and later in time. The three-dimensional structure of the stagnated Z pinch depends on the initial wire-array configuration and implosion scenario. Small-scale density perturbations were found in the precursor plasma and in the stagnated Z pinch. Development of instabilities is in agreement with three-dimensional magnetohydrodynamic simulations.
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Affiliation(s)
- V V Ivanov
- Department of Physics, University of Nevada, Reno, Nevada 89557, USA
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Ivanov VV, Hakel P, Mancini RC, Chittenden JP, Anderson A, Durmaz T, Wiewior P, Papp D, Altemara SD, Astanovitskiy AL, Chalyy O. Measurement of the ionization state and electron temperature of plasma during the ablation stage of a wire-array Z pinch using absorption spectroscopy. Phys Rev Lett 2011; 106:225005. [PMID: 21702609 DOI: 10.1103/physrevlett.106.225005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2011] [Indexed: 05/31/2023]
Abstract
Wire-array plasmas were investigated in the nonradiative ablation stage via x-ray absorption spectroscopy. A laser-produced Sm plasma was used to backlight Al wire arrays. The Sm spectrum was simultaneously observed by two spectrometers: one recorded the unattenuated spectrum and the other the transmission spectrum with 1.45-1.55 keV K-shell absorption lines. Analysis of absorption spectra revealed electron temperature in the range of 10-30 eV and the presence of F-, O-, N- and C-like Al ions in the absorbing plasma. A comparison of this electron temperature with the postprocessed absorption spectra of a 2D MHD simulation yields results in general agreement with the data analysis.
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Affiliation(s)
- V V Ivanov
- Department of Physics, University of Nevada, Reno, Nevada 89557, USA
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Lancaster KL, Sherlock M, Green JS, Gregory CD, Hakel P, Akli KU, Beg FN, Chen SN, Freeman RR, Habara H, Heathcote R, Hey DS, Highbarger K, Key MH, Kodama R, Krushelnick K, Nakamura H, Nakatsutsumi M, Pasley J, Stephens RB, Storm M, Tampo M, Theobald W, Van Woerkom L, Weber RL, Wei MS, Woolsey NC, Yabuuchi T, Norreys PA. Effect of reentrant cone geometry on energy transport in intense laser-plasma interactions. Phys Rev E Stat Nonlin Soft Matter Phys 2009; 80:045401. [PMID: 19905383 DOI: 10.1103/physreve.80.045401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2009] [Indexed: 05/28/2023]
Abstract
The energy transport in cone-guided low- Z targets has been studied for laser intensities on target of 2.5x10(20) W cm(-2). Extreme ultraviolet (XUV) imaging and transverse optical shadowgraphy of the rear surfaces of slab and cone-slab targets show that the cone geometry strongly influences the observed transport patterns. The XUV intensity showed an average spot size of 65+/-10 microm for slab targets. The cone slabs showed a reduced spot size of 44+/-10 microm. The shadowgraphy for the aforementioned shots demonstrate the same behavior. The transverse size of the expansion pattern was 357+/-32 microm for the slabs and reduced to 210+/-30 microm. A transport model was constructed which showed that the change in transport pattern is due to suppression of refluxing electrons in the material surrounding the cone.
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Affiliation(s)
- K L Lancaster
- STFC Rutherford Appleton Laboratory, Chilton, Oxon, United Kingdom
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Ivanov VV, Sotnikov VI, Kindel JM, Hakel P, Mancini RC, Astanovitskiy AL, Haboub A, Altemara SD, Shevelko AP, Kazakov ED, Sasorov PV. Implosion dynamics and x-ray generation in small-diameter wire-array Z pinches. Phys Rev E Stat Nonlin Soft Matter Phys 2009; 79:056404. [PMID: 19518573 DOI: 10.1103/physreve.79.056404] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2008] [Revised: 02/06/2009] [Indexed: 05/27/2023]
Abstract
It is known from experiments that the radiated x-ray energy appears to exceed the calculated implosion kinetic energy and Spitzer resistive heating [C. Deeney, Phys. Rev. A 44, 6762 (1991)] but possible mechanisms of the enhanced x-ray production are still being discussed. Enhanced plasma heating in small-diameter wire arrays with decreased calculated kinetic energy was investigated, and a review of experiments with cylindrical arrays of 1-16 mm in diameter on the 1 MA Zebra generator is presented in this paper. The implosion and x-ray generation in cylindrical wire arrays with different diameters were compared to find a transition from a regime where thermalization of the kinetic energy is the prevailing heating mechanism to regimes with other dominant mechanisms of plasma heating. Loads of 3-8 mm in diameter generate the highest x-ray power at the Zebra generator. The x-ray power falls in 1-2 mm loads which can be linked to the lower efficiency of plasma heating with the lack of kinetic energy. The electron temperature and density of the pinches also depend on the array diameter. In small-diameter arrays, 1-3 mm in diameter, ablating plasma accumulates in the inner volume much faster than in loads of 12-16 mm in diameter. Correlated bubblelike implosions were observed with multiframe shadowgraphy. Investigation of energy balance provides evidence for mechanisms of nonkinetic plasma heating in Z pinches. Formation and evolution of bright spots in Z pinches were studied with a time-gated pinhole camera. A comparison of x-ray images with shadowgrams shows that implosion bubbles can initiate bright spots in the pinch. Features of the implosions in small-diameter wire arrays are discussed to identify mechanisms of energy dissipation.
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Affiliation(s)
- V V Ivanov
- Department of Physics, University of Nevada, Reno, Nevada 89506, USA
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