Onset of the magnetized arc and its effect on the momentum of a low-power two-stage pulsed magneto-plasma-dynamic thruster

A new type of plasma accelerator---a low-power (<300.28em0exW), miniature (cm-sized), two-stage pulsed magneto-plasma-dynamic thruster---has been proposed. Being magnetized by an axially symmetric dc magnetic field of {~}200 mT, the vacuum arc discharge demonstrates a threshold behavior: Parameters such as thrust and the thrust-to-power ratio rapidly jump after a certain dc voltage ({~}30 V) is applied on the accelerating electrode. We show that such an effect improves the thrust (from {~}2 to {~}210 {}N), efficiency (from {~}1% to 50%), and thrust-to-power ratio (from {~}0.5 to {~}18 {}N/W).