Influence of cyclic ignition and steady-state operation on a 1-2 A barium tungsten hollow cathode

Booming low-power electric propulsion systems require 1-2 A hollow cathodes. Such cathodes are expected to go through more frequent ignitions in the low orbit, but the impact of cyclic ignitions on such 1-2 A barium tungsten hollow cathodes with a heater was not clear. In this study, a 12,638-cyclic ignition test and a 6,000 hour-long life test on two identical cathodes were carried out. The discharge voltage of the cathode and the erosion of the orifice after cyclic ignition were all larger than that of the cathode after stable operation. This indicated that the impact of cycle ignition on the discharge performance of a low current BaO-W cathode with a heater was higher than that of stable operation. The results of the ion energy distribution function measured during the ignition period indicated that the main reason for the orifice expansion was ion bombardment. Therefore, it was necessary to pay attention to the number of ignitions for the lifetime of this kind of cathode.