Shock Structure in a Collisional, Magnetised Laboratory Plasma

Shocks are ubiquitous in astrophysical, space and laboratory plasmas and are typical of systems in which high velocity flows interact. We present results from a laboratory study of shock structure in a collisional HED plasma. Supersonic, super-Alfvénic plasma flows (n e ~ 1×10 18 cm -3 , B ~ 2 T, v = 50 - 100 kms -1 ,T ~ 10 eV) are produced by current driven ablation at the MAGPIE pulsed power facility and shocks are studied by placing obstacles into these flows. The plasma flows are highly collisional, with (m.f.p << resistive/thermal diffusion lengths << system size). This hierarchy of scales leads to shocks in which a combination of dissipation mechanisms may determine the shock structure. Laser probing diagnostics, including interferometry, optical Thomson scattering and Faraday rotation polarimetry provide detailed measurements of plasma parameters in both the upstream and downstream plasmas. We investigate the effects of different dissipation mechanisms as well as the effect of radiative cooling on shock structure.