The structure of 3-D collisional magnetized bow shocks in pulsed-power-driven plasma flows
File(s)Datta_JPP_2022_accepted.pdf (3.86 MB)
Accepted version
Author(s)
Type
Journal Article
Abstract
We investigate three-dimensional (3-D) bow shocks in a highly collisional magnetized aluminium plasma, generated during the ablation phase of an exploding wire array on the MAGPIE facility (1.4 MA, 240 ns). Ablation of plasma from the wire array generates radially diverging, supersonic ( MS∼7
), super-Alfvénic ( MA>1
) magnetized flows with frozen-in magnetic flux ( RM≫1
). These flows collide with an inductive probe placed in the flow, which serves both as the obstacle that generates the magnetized bow shock, and as a diagnostic of the advected magnetic field. Laser interferometry along two orthogonal lines of sight is used to measure the line-integrated electron density. A detached bow shock forms ahead of the probe, with a larger opening angle in the plane parallel to the magnetic field than in the plane normal to it. Since the resistive diffusion length of the plasma is comparable to the probe size, the magnetic field decouples from the ion fluid at the shock front and generates a hydrodynamic shock, whose structure is determined by the sonic Mach number, rather than the magnetosonic Mach number of the flow. The 3-D simulations performed using the resistive magnetohydrodynamic (MHD) code Gorgon confirm this picture, but under-predict the anisotropy observed in the shape of the experimental bow shock, suggesting that non-MHD mechanisms may be important for modifying the shock structure.
), super-Alfvénic ( MA>1
) magnetized flows with frozen-in magnetic flux ( RM≫1
). These flows collide with an inductive probe placed in the flow, which serves both as the obstacle that generates the magnetized bow shock, and as a diagnostic of the advected magnetic field. Laser interferometry along two orthogonal lines of sight is used to measure the line-integrated electron density. A detached bow shock forms ahead of the probe, with a larger opening angle in the plane parallel to the magnetic field than in the plane normal to it. Since the resistive diffusion length of the plasma is comparable to the probe size, the magnetic field decouples from the ion fluid at the shock front and generates a hydrodynamic shock, whose structure is determined by the sonic Mach number, rather than the magnetosonic Mach number of the flow. The 3-D simulations performed using the resistive magnetohydrodynamic (MHD) code Gorgon confirm this picture, but under-predict the anisotropy observed in the shape of the experimental bow shock, suggesting that non-MHD mechanisms may be important for modifying the shock structure.
Date Issued
2022-12
Date Acceptance
2022-10-17
Citation
Journal of Plasma Physics, 2022, 88 (6)
ISSN
0022-3778
Publisher
Cambridge University Press
Journal / Book Title
Journal of Plasma Physics
Volume
88
Issue
6
Copyright Statement
Copyright © 2022 Cambridge University Press. This article has been published in a revised form in Journal of Plasma Physics https://doi.org/10.1017/S0022377822001118. 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:000881710300001&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=a2bf6146997ec60c407a63945d4e92bb
Subjects
astrophysical plasmas
ASTROPHYSICS
INSTABILITIES
JETS
MODEL
Physical Sciences
Physics
Physics, Fluids & Plasmas
plasma nonlinear phenomena
plasma simulation
Science & Technology
SUPERNOVA HYDRODYNAMICS
WAVES
Publication Status
Published
Article Number
ARTN 905880604
Date Publish Online
2022-11-11