LOW-FREQUENCY DRIFT-WAVE INSTABILITY IN DC DISCHARGES

The result for the permittivity of weakly ionized, weakly magnetized p lasmas obtained by Kiss'ovski and Shivarova (1995) is analysed aiming at a description of the behaviour of low-frequency instabilities in de discharges maintained at comparatively high gas pressures. The spectr um and the condition of instability of low-frequency drift waves arisi ng in the discharges under conditions of comparatively high collision frequency nu(in) similar to omega(ci) and finite ion gyroradius rho(i) < R are derived. (Here omega(ci) and rho(i) are the ion gyrofrequency and gyroradius, respectively, nu(in) is the ion-neutral collision fre quency and R is the plasma column radius.) Results from numerical anal ysis are compared with experimental data previously obtained (Kiss'ovs ki et al 1994).