We investigated the prebreakdown processes in a fast compact pulsed capillary discharge, operating in a 1.6 mm inner diameter, 35 mm long alumina capillary, at 15 kV applied voltage. Argon, at pressure in the 300-1000 mTorr range is used inside the capillary. On axis discharge initiation is assisted by axial electron beams, which originate from a hollow cathode region. Ionization Waves (IW) are investigated using a capacitive probe array. Four probes are located along the capillary, thus providing both time and space resolution. Two different types of IW are observed, depending on the voltage polarity. If the grounded capillary shield is at anode potential, a fast anode directed IW is observed, with characteristic velocity of hundreds of centimeters per microsecond. If the polarity is reversed and the grounded capillary shield is now at cathode potential, a cathode directed IW is observed, with characteristic velocity of a few centimeters per microsecond. General features of the observed IW are successfully described by a numerical calculation based on a quasi-one-dimensional theoretical model of shielded capillary discharge.
|Original language||English GB|
|Title of host publication||American Physical Society, 42nd Annual Meeting of the APS Division of Plasma Physics combined with the 10th International Congress on Plasma Physics October 23 - 27, 2000 Québec City, Canada Meeting ID: DPP00|
|State||Published - 1 Oct 2000|