IMPROVEMENT OF HALL THRUSTER PERFORMANCE

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A magnetic circuit that largely influences Hall thruster performance was designed by using two-dimensional FEM magnetic analysis code which was developed previously. A solenoidal coil was positioned at the center of acceleration channel in order to have high radial magnetic fields applied on it.Based on the above circuit design, the acceleration channel of a thruster was designed and fabricated. In addition, power supplies for plasma production, ion acceleration, and neutralization were ordered and assembled.The thruster was operated in the vacuum system which consists of a 0.8 m diam. and 2.5 m long chamber and 10,000 1/s pumping system. We obtained stable arc discharge as well as normal plasma production and ion beam extraction. Also, discharge voltage-current characteristics were examined and show a general tendency for this kind of thruster.Increasing an input power up to 1.5kW, thrust measurement was done to estimate thruster performance. Ion beam current was also measured to obtain acceleration efficiency and to investigate the effect of channel geometry, field strength, and operating conditions on it.A hollow cathode was installed on the thruster in place of a filament cathode. With the hollow cathode, a maximum thrust efficiency of 34 % was obtained when xenon gas was used as the propellant.