The current-voltage characteristics of hollow cathode discharges and t
heir predischarges in argon under de and pulsed conditions were found
to have a positive slope at pressures up to approximately 50 Ton, and
currents up to 20 mA, at a hole diameter of 0.7 mm. In this range of p
ressure and current, parallel operation of hollow cathode discharges,
without ballast, was demonstrated. Scaling to higher pressure is possi
ble by reducing the hole diameter. Pulsed experiments with an array of
cathode rings of 75 mu m diameter allowed us to obtain parallel opera
tion of more than 50 discharges at a pressure of 350 Ton in air. (C) 1
996 American Istitute of Physics.