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

The 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 heater was not clear. In this study, a 12638-cyclic ignition test and a 6000-hour-long life test on two identical cathodes were carried out. The discharge voltage of the cathode and the erosion of orifice after cyclic ignition were all larger than that of cathode after stable operation. This indicated that the impact of cycle ignition on the discharge performance of low current BaO-W cathode with 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, the number of ignitions needed to be paid attention to for the lifetime of this kind of cathodes.