Thermalization of the kinetic energy of a plasma flow by a magnetic mirror field in BSG-I experiments

Abstract

The purpose of the experiment using the BSG-I device described here is to study the expansion of a plasma, produced in a strong magnetic field by a theta pinch, into a weak magnetic channel and the thermalization of the kinetic energy of this plasma flow by a magnetic mirror field. The plasma, to which the fluid model is applicable, treated here is collision dominated and low-β. Shock phenomena due to the mirror field at the far end of the device are observed by several kinds of measurements and it was concluded that some part of the kinetic energy of the plasma flow was changed to thermal energy by the shock phenomenon. Plasma parameters measured in front of and behind the shock front were consistent with the Rankine-Hugoniot relations. Thus the ion temperature rises after the shock and approaches that of the initial plasma as produced in the theta pinch region before the expansion.