Particle Diffusion in a Low Pressure Crossfield Plasma Heating Device

Abstract

The Slepian discharge rotating magnetoplasma is investigated in helium for neutral gas pressures of 3.3×10-1 and 6.7×10-2 torr with end wall potentials to +300 volts d. c. and an applied axial magnetic field of 0 to 6000 gauss. A cold cathode field emission Penning discharge radial ion source is incorporated within the apparatus as a central ion source. Ion and electron diffusion rates across and along the applied field lines are determined as functions of applied end wall potential, Penning discharge current and axial field strength. For pressures of 3.3×10-1 and 6.7×10-2 torr, anomalous increases in radial current with increasing magnetic field are not observed, while distinct minima in end wall currents are found suggesting a critical value of magnetic field strength after which the character of the particle flow to the end walls markedly changes.