EXPERIMENT ON INTERACTION OF A MAGNETIZED SPHERE WITH A SUPERSONIC PLASMA-FLOW

Today's increased knowledge of the structure and dynamics of the magnetosphere as well as advanced techniques of large volume plasma production and plasma diagnostics led the authors to start an experimental study on the interaction of a fast plasma beam with a magnetized sphere. The experiment reported in this paper relates to a case where the transition from β > 1 to β ≪ 1 and MA> 1 to MA ≪ 1 is achieved by reducing substantially the initial magnetization of a low density plasma beam. A pulsed magnetic dipole was exposed to an argon plasma beam of velocities ranging from 9.8 to 31 km s-1. The distribution of the d.c. electric potential in the upstream and downstream interaction regions was measured by means of a spherical high input impedance electric probe. The variation of the potential as a function of the distance from the dipole axis and plasma beam velocity is discussed in terms of the magnetic Reynolds number and its dependence on beam velocity and plasma conductivity. © 1978.