SPATIAL STABILIZATION OF TOWNSEND AND GLOW-DISCHARGES WITH A SEMICONDUCTING CATHODE

The physical processes determining the functions of an ionization syst em and especially the discharge stabilization by the distributed resis tance of a semiconducting cathode in such a system are studied. The cu rrent-voltage (I-U) characteristics of the system with a semiconductin g GaAs cathode are obtained experimentally as functions of the gap pre ssure P (16-760 Torr) and inter-electrode distance d (10 mu m to 5 mm) , which are varied for the first time over very wide ranges. The exper iments showed that the presence of the distributed resistance affects the passage of the discharge current so that the discharge glows unifo rmly throughout the cathode surface and is not divided into separate f ilaments. The loss of stability was primarily due to the formation of a space charge of positive ions in the discharge gap which changed the discharge from the Townsend to the glow type.