[10p-S301-3~12] 8.1 Plasma production and diagnostics

[10p-S301-6] Application of Iridium-Cerium Alloy to Electron Source for Electric Rocket Propulsion

〇Hiroki Watanabe¹, Shinatora Cho¹, Yoshiki Matsunaga¹, Yasushi Ohkawa¹, Yuki Tao², Fumiaki Kudo², Kenji Koga², Yabu Satoshi² (1.JAXA, 2.KOBELCO Res. Inst.)

Keywords:Thermionic Emitter, Plasma Cathode, Electric Rocket Propulsion

Hollow cathodes are typically used as electron sources in ion and Hall thrusters to ionize propellant and neutralize the ion beam. A plasma is generated within the hollow cathode through thermionic emission. We propose to use iridium-cerium alloy (CeIr₂) in the thermionic emitter of a hollow cathode. The experimental comparison of insert materials showed that the operating temperature and discharge voltage of the hollow cathode with the CeIr₂ insert was lower than those with the lanthanum hexaboride insert at a constant discharge current. The stable operation of the 1-kW Hall thruster with an internally mounted hollow cathode using the CeIr₂ insert was verified. The deposition and modification on the downstream inner surface of the CeIr₂ insert were not observed after Hall thruster firing when the oxygen mixed into the propellant was reduced.