Zl. Petrovic et Av. Phelps, OSCILLATIONS OF LOW-CURRENT ELECTRICAL DISCHARGES BETWEEN PARALLEL-PLANE ELECTRODES .1. DC DISCHARGES, Physical review. E, Statistical physics, plasmas, fluids, and related interdisciplinary topics, 47(4), 1993, pp. 2806-2815
The oscillatory behavior of dc discharges between parallel-plane elect
rodes (1 cm spacing) at low pressures (0.5-3 Torr) is measured and com
pared with models. For hydrogen these discharges are unstable for wide
ranges of discharge current below 0.2 mA/cm2 and external circuit res
istances above almost-equal-to 4000 OMEGA. Lateral constrictions of th
e discharge occur over a much more limited range of currents and press
ures than do oscillations. Laser-induced photoelectron pulses produce
damped oscillations for discharge currents below those at which self-s
ustained oscillations are observed. The frequency of the oscillations
varies approximately as the square root of the discharge current and t
he damping of the oscillations increases with the discharge current. T
hese results agree with simple models developed in an accompanying pap
er [this issue, Phelps, Petrovic, and Jelenkovic, Phys. Rev. E 47, 282
5 (1993)]. Some data are presented for argon and nitrogen.