Performance comparison between standard and magnetically shielded 200 W Hall thrusters with BN-SiO2 and graphite channel walls

Lou Grimaud (1) , Stéphane Mazouffre (1)

1 ICARE - Institut de Combustion, Aérothermique, Réactivité et Environnement

Magnetic shielding is a specific magnetic topology that has the potential to produce a severalfold increase in the lifespan of Hall thruster. It reduces wall erosion and has been shown to result in similar performances as standard unshielded thrusters in the 5 to 15 kW discharge power range. A direct comparison of the performances of two 200 W shielded and unshielded Hall thrusters is presented here. The effects of replacing the usual BN-SiO 2 walls with graphite are investigated on both type of thrusters. The unshielded ISCT200-US thruster has a peak anode efficiency of 39% and a specific impulse of 1400 s at 250 W with the ceramic discharge channel. It however suffers from the change to graphite wall, the peak efficiency falls down to 31% (1360 s specific impulse) as the discharge current increase by nearly 25%. The magnetically shielded ISCT200-MS performances are significantly lower than its unshielded counterpart. It only reaches 24% anode efficiency and 1020 s specific impulse at 250 W. Interestingly the switch to graphite has little effects on its performances below 300 V. An increase in thrust is observed at 300 V with graphite walls. It raises the anode efficiency to 28% at 320 W (1240 s specific impulse). We propose an explanation as to why the small shielded thruster shows lower performances than an equivalent unshielded one.

Mots clés: Hall thruster; Electric propulsion; Magnetic Shielding; Wall materials

Domaines: Sciences de l'ingénieur [physics]; Plasmas

Lou Grimaud, Stéphane Mazouffre. Performance comparison between standard and magnetically shielded 200 W Hall thrusters with BN-SiO2 and graphite channel walls. Vacuum, 2018, 155, pp.514-523. ⟨10.1016/j.vacuum.2018.06.056⟩. ⟨hal-02409585⟩