Observation of subcritical shocks in a collisional laboratory plasma: scale dependence near the resistive length
File(s)
Accepted version
Author(s)
Type
Journal Article
Abstract
We present a study of subcritical shocks in a highly collisional laboratory plasma with a dynamically significant magnetic field. Shocks were produced by placing cylindrical obstacles into the supermagnetosonic ( MMS∼1.9
) outflow from an inverse wire array z-pinch at the MAGPIE pulsed power facility ( ne∼8.5×1017cm−3
, v∼45kms−1
). We demonstrate the existence of subcritical shocks in this regime and find that secondary stagnation shocks form in the downstream which we infer from interferometry and optical Thomson scattering measurements are hydrodynamic in nature. The subcritical shock width is found to be approximately equal to the resistive diffusion length and we demonstrate the absence of a jump in hydrodynamic parameters. Temperature measurements by collective optical Thomson scattering showed little temperature change across the subcritical shock ( <10%
of the ion kinetic energy) which is consistent with a balance between adiabatic and Ohmic heating and radiative cooling. We demonstrate the absence of subcritical shocks when the obstacle diameter is less than the resistive diffusion length due to decoupling of the magnetic field from the plasma. These findings are supported by magnetohydrodynamic simulations using the Gorgon and AstroBEAR codes and discrepancies between the simulations and experiment are discussed.
) outflow from an inverse wire array z-pinch at the MAGPIE pulsed power facility ( ne∼8.5×1017cm−3
, v∼45kms−1
). We demonstrate the existence of subcritical shocks in this regime and find that secondary stagnation shocks form in the downstream which we infer from interferometry and optical Thomson scattering measurements are hydrodynamic in nature. The subcritical shock width is found to be approximately equal to the resistive diffusion length and we demonstrate the absence of a jump in hydrodynamic parameters. Temperature measurements by collective optical Thomson scattering showed little temperature change across the subcritical shock ( <10%
of the ion kinetic energy) which is consistent with a balance between adiabatic and Ohmic heating and radiative cooling. We demonstrate the absence of subcritical shocks when the obstacle diameter is less than the resistive diffusion length due to decoupling of the magnetic field from the plasma. These findings are supported by magnetohydrodynamic simulations using the Gorgon and AstroBEAR codes and discrepancies between the simulations and experiment are discussed.
Date Issued
2023-08
Date Acceptance
2023-07-11
Citation
Journal of Plasma Physics, 2023, 89 (4)
ISSN
0022-3778
Publisher
Cambridge University Press
Journal / Book Title
Journal of Plasma Physics
Volume
89
Issue
4
Copyright Statement
Copyright © 2023 Cambridge University Press. This article has been published in a revised form in Journal of Plasma Physics https://doi.org/10.1017/S0022377823000740. This version is free to view and download for private research and study only. Not for re-distribution, re-sale or use in derivative works.
Identifier
https://www.webofscience.com/api/gateway?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:001045059500001&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=a2bf6146997ec60c407a63945d4e92bb
Subjects
astrophysical plasmas
FLOW
Physical Sciences
Physics
Physics, Fluids & Plasmas
plasma nonlinear phenomena
plasma waves
Science & Technology
TRANSPORT
WAVES
Publication Status
Published
Article Number
915890401
Date Publish Online
2023-08-10