Tailoring of Magnetic Field for Performance Improvement in a Small Hall Thruster Plasma

Tailoring of the magnetic field was attempted for performance improvement in a 500-W class small Hall thruster (KmHT-60). Two different tailored magnetic field configurations, both having field lines convex toward the anode but with different curvatures, resulted in different thrusts, anode specific impulses, and anode efficiencies; the corresponding values were 20.7 mN, 2150 s, and 51.5% at an anode power of 423 W in the case of the better aligned magnetic field, which were 27%, 21%, and 54% higher than those in the other magnetic field configuration, respectively. Efficiency analysis using far-field plume measurements showed that the difference in the thruster performance is mostly due to the enhancements in the current utilization efficiency caused by the suppression of the electron leakage current and the high propellant utilization efficiency due to the increased ion current.