The Influence of Transverse Magnetic Fields on the Current-Voltage Characteristics of Glow Discharges

In low pressure discharges, operated in electronegative gas mixtures to the right of the Paschen curve minimum, the discharge resistance can be increased by application of transverse magnetic fields. In this range of operation, both the mean free path and the larmor radius are small compared to the discharge dimensions. The relationship between the electric field and the magnetic field is therefore controlled by electron- molecule collisional processes. Specifically, the magnetically induced increase in the discharge resistance is caused by a downward shift of the electron energy distribution which leads to an increase in attachment and a reduction in ionization. In this work the effect of a transverse magnetic field on a glow discharge has been investigated. Measurements of the steady-state current-voltage characteristics of glow discharges in transverse magnetic fields have been performed in He and He/SF6 gas mixtures. The experimental setup and diagnostics are described, and the experimental results are presented. The experimental results indicate an increase of discharge voltage in He/SF6 mixture at 8 torr of 2.5 kV/Tesla. This is in good agreement with Monte Carlo calculations of the electric field intensity in the positive column.