Axial Magnetic Field Effect on Vacuum Arc Thruster Performance

The performance gain of co-axial vacuum arc thruster in external axial magnetic field is analyzed by power and direct thrust measurements. Thruster geometry is actively controlled and inspected using laser profilometry. Peak performance is shown to be obtained in magnetic induction of 0.1 - 0.2 T, with measured thrust of 21 uN at arc power of 2.7 W, and thruster efficiency of ~ 4 %. The performance gain is attributed to ion beam focusing, increased erosion rate, and ion acceleration due to the axial magnetic field.