Plasma-Ion Oscillation in a Drifted Plasma

Abstract

The plasma-ion oscillations were observed in a diode-type discharge tube varying the longitudinal magnetic field or the cathode temperature. When the magnetic field strength was increased, the oscillation frequency increased up to a critical value at constant discharge current and the oscillation disappeared at higher magnetic fields. A similar variation in the oscillation was observed when the cathode temperature was decreased. These frequency shifts are qualitatively explained. Considering the electron drift velocity, the excitation mechanism of the plasma-ion oscillation is also discussed using the theory by Fried and Gould.