Hall Effect and Electron Drift Velocities in the Plasma of the Positive Column

The Hall potential has been observed for positive columns established at pressures near 1 Torr in helium, neon, argon, and nitrogen. Simultaneous measurement of the density of electrons in the column by the microwave cavity technique has given an independent determination of the electron drift velocity. The proportionality factor α between the Hall field measured and the product of the drift velocity and applied magnetic field has been determined. The factor α for the case of helium was 0.50 ± 0.07, which is in agreement with theory. For neon, α ≅ 0.60, also in agreement with theory. The column established in argon or nitrogen was generally noisy, but α ≅ 0.5 and showed a tendency to decrease with decreasing gas pressure, also expected from theory. Electron collision frequency for momentum transfer was determined by microwave methods and also from the dc mobility. The agreement was satisfactory.