Because of high emission current density, LaB6 hollow cathode has been widely used in the field of space electric propulsion. Aiming at the phenomenon of voltage fluctuation in intermittent discharge, firstly, amplitudes and law of voltage fluctuation in different intervals were analyzed to determine causes of voltage fluctuation. Then, the surface composition and poisoning mechanism of LaB6 emitter were analyzed, it is concluded that after exposure to the atmosphere, a large amount of oxygen was absorbed on the surface of LaB6 emitter, and a strong dipole moment was formed between surface, resulting in surface work function of emitter increases accordingly. Thus, the anode voltage will rise when working again. Oxygen and oxides can be removed from the surface of LaB6 emitter by heating or ion bombardment. The hollow cathode performance and ion thruster reliability can be improved by this method.
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杨威,史楷,谷增杰,等. LaB6空心阴极放电电压波动现象及发生机理[J]. 科学技术与工程, 2020, 20(33): 13914-13918. YANG Wei, 史楷, GU Zeng-Jie, et al. Study on discharge voltage fluctuation of LaB6 Hollow Cathode[J]. Science Technology and Engineering,2020,20(33):13914-13918.