Shock and Current Sheet Structure in a Theta-Pinch Configuration

Abstract

The structure of a current sheet during the compression of an argon plasma with no bias field is studied in a theta-pinch configuration. The profiles of magnetic field, particle density, mean velocity, and temperature are measured. No perturbation in front of the sheet is observed. It is shown that the initial gas passes through the sheet, emerging downstream, with a small relative velocity. During this acceleration process, the ion and electron temperatures remain small. The initial energy of ions relative to the sheet is thoroughly converted into thermal electron energy and in turn is radiated away through excitation of argon ions. The plasma motion, as well as the structure of the sheet, can be explained using fluid equations and Ohm's law. These equations are similar to those which govern the structure of a transverse shock wave with the resistivity as the only dissipative process.