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Hua R, Bailly-Grandvaux M, May J, Sherlock M, Dozières M, McGuffey C, Ping Y, Mori W, Beg FN. Structures of strong shocks in low-density helium and neon gases. Phys Rev E 2023; 108:035202. [PMID: 37849193 DOI: 10.1103/physreve.108.035202] [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] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 07/28/2023] [Indexed: 10/19/2023]
Abstract
Strong shocks are essential components in many high-energy-density environments such as inertial confinement fusion implosions. However, the experimental measurements of the spatial structures of such shocks are sparse. In this paper, the soft x-ray emission of a shock front in a helium gas mixture (90% helium, 10% neon) and a pure neon gas was spatially resolved using an imaging spectrometer. We observe that the shock width in the helium mixture gas is about twice as large as in the pure neon gas. Moreover, they exhibit different precursor layers, where electron temperature greatly exceeds ion temperature, extending for more than ∼350µm with the helium gas mixture but less than 30µm in the pure neon. At the shock front, calculations show that the electrons are strongly collisional with mean-free path two orders of magnitude shorter than the characteristic length of the shock. However, the helium ions can reach a kinetic regime as a consequence of their mean-free path being comparable to the scale of the shock. A radiation-hydrodynamic simulation demonstrates the impact of thermal conduction on the formation of the precursors with charge state, Z, playing a major role in heat flow and the precursor formation in both the helium mixture and the pure neon gases. Particle-in-cell simulations are also performed to study the ion kinetic effects on the formation of the observed precursors. A group of fast-streaming ions is observed leading the shock only in the helium gas mixture. Both effects explain the longer precursor layer in the helium shock.
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Affiliation(s)
- R Hua
- Center for Energy Research and Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, California 92093, USA
| | - M Bailly-Grandvaux
- Center for Energy Research and Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, California 92093, USA
| | - J May
- Department of Physics, University of California, Los Angeles, Los Angeles, California 90095, USA
| | - M Sherlock
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - M Dozières
- Center for Energy Research and Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, California 92093, USA
| | - C McGuffey
- Center for Energy Research and Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, California 92093, USA
| | - Y Ping
- Lawrence Livermore National Laboratory, Livermore, California 94550, USA
| | - W Mori
- Department of Physics, University of California, Los Angeles, Los Angeles, California 90095, USA
| | - F N Beg
- Center for Energy Research and Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, California 92093, USA
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Russell DR, Burdiak GC, Carroll-Nellenback JJ, Halliday JWD, Hare JD, Merlini S, Suttle LG, Valenzuela-Villaseca V, Eardley SJ, Fullalove JA, Rowland GC, Smith RA, Frank A, Hartigan P, Velikovich AL, Chittenden JP, Lebedev SV. Perpendicular Subcritical Shock Structure in a Collisional Plasma Experiment. Phys Rev Lett 2022; 129:225001. [PMID: 36493430 DOI: 10.1103/physrevlett.129.225001] [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: 01/19/2022] [Revised: 10/14/2022] [Accepted: 10/25/2022] [Indexed: 06/17/2023]
Abstract
We present a study of perpendicular subcritical shocks in a collisional laboratory plasma. Shocks are produced by placing obstacles into the supermagnetosonic outflow from an inverse wire array z pinch. We demonstrate the existence of subcritical shocks in this regime and find that secondary shocks form in the downstream. Detailed measurements of the subcritical shock structure confirm the absence of a hydrodynamic jump. We calculate the classical (Spitzer) resistive diffusion length and show that it is approximately equal to the shock width. We measure little heating across the shock (<10% of the ion kinetic energy) which is consistent with an absence of viscous dissipation.
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Affiliation(s)
- D R Russell
- Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom
| | - G C Burdiak
- First Light Fusion Ltd, Yarnton, Kidlington OX5 1QU, United Kingdom
| | - J J Carroll-Nellenback
- Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627, USA
| | - J W D Halliday
- Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom
| | - J D Hare
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - S Merlini
- Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom
| | - L G Suttle
- Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom
| | | | - S J Eardley
- Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom
| | - J A Fullalove
- Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom
| | - G C Rowland
- Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom
| | - R A Smith
- Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom
| | - A Frank
- Department of Physics and Astronomy, University of Rochester, Rochester, New York 14627, USA
| | - P Hartigan
- Department of Physics and Astronomy, Rice University, Houston, Texas 77005-1892, USA
| | - A L Velikovich
- Plasma Physics Division, U.S. Naval Research Laboratory, Washington, DC 20375, USA
| | - J P Chittenden
- Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom
| | - S V Lebedev
- Blackett Laboratory, Imperial College London, London SW7 2AZ, United Kingdom
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Zhang WS, Cai HB, Du B, Kang DG, Zou SY, Zhu SP. Full particle-in-cell simulation of the formation and structure of a collisional plasma shock wave. Phys Rev E 2021; 103:023213. [PMID: 33735973 DOI: 10.1103/physreve.103.023213] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 02/03/2021] [Indexed: 11/07/2022]
Abstract
The formation and structure of a collisional shock wave in a fully ionized plasma is studied via full particle-in-cell simulations, which allows the complex momentum and energy transfer processes between different charged particles to be treated self-consistently. The kinetic energy of the plasma flow drifting towards a reflecting piston is found to be rapidly converted into thermal motion under the cooperative effects of ion-ion collisions, ion-electron collisions, and electric field charged-particle interactions. The subsequent shock evolution is influenced by the "precursor" ion beam before a quasisteady state is reached. The shock wave structure is then analyzed from a two-fluid transport viewpoint, which is found to be affected by "flux-limiting" electron transport, the nonthermal ions, and the charge separation electric field.
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Affiliation(s)
- Wen-Shuai Zhang
- Institute of Applied Physics and Computational Mathematics, Beijing 100094, China
| | - Hong-Bo Cai
- Institute of Applied Physics and Computational Mathematics, Beijing 100094, China
| | - Bao Du
- Institute of Applied Physics and Computational Mathematics, Beijing 100094, China
| | - Dong-Guo Kang
- Institute of Applied Physics and Computational Mathematics, Beijing 100094, China
| | - Shi-Yang Zou
- Institute of Applied Physics and Computational Mathematics, Beijing 100094, China
| | - Shao-Ping Zhu
- Institute of Applied Physics and Computational Mathematics, Beijing 100094, China
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