The magnetohydrodynamics of high energy density plasmas produced by radial foil configurations

Summary form only given: Radial foil configurations have been used recently in pulsed- power generators to study high energy density plasmas. The setup uses a thin metallic foil and two electrodes: the outer electrode, which has little impact on plasma dynamics, and the inner electrode, where all the discharge current is focused. This focusing effect depends on the diameter of the central electrode, in turn controlling the energy deposition inside the foil material. Using the COBRA generator (1MA with 100 ns rise time) and a "pin" electrode, 1 mm in diameter, it is possible to produce current densities with hundreds of MA/mm2 and 400-T magnetic fields at the foil center. The resulting JxB force propels foil material and plasma vertically, with velocities in the order of 400 km/s. The plasma formation and subsequent focus produce radiations with energies close to 8 keV, in a 1-mm plasma column. Another advantage of radial foil geometries is the diagnostic access. Due to the open configuration, the plasma dynamics is observable from beginning to end, by a wide range of diagnostics. Data from laser back-lighter and interferometer, B-dot probes, X-UV and streak cameras will be analyzed to describe and understand the magneto-hydrodynamics of radial foils. Particular attention will be given to the physics of plasma jets, shocks and magnetic reconnections.