Pulsed Inductive Thruster Development (Advanced Electric Propulsion Technology - High Thrust).

This report describes the results of an experimental investigation of the operation and efficiency of a large impulsive plasma thruster. The thruster uses a one-meter diameter flat spiral coil through which current is pulsed by discharging a 4000 Joule capacitor bank using a spark gap switch. The plasma is driven through inductive coupling rather than with electrodes so as to avoid erosion and energy loss mechanisms that might be undesirable for spacecraft uses. The object of the work was to compare thruster efficiency with pulsed gas injection to the static fill efficiency of a similar one-meter, diameter, coil thruster tested earlier. Using only the first half-cycle impulse, the static fill efficiency had been 38 at 1730 seconds Isp. Using the impulse of three half-cycles for the present pulsed injection test 0.190, 0.033 and 0.011 Newton-seconds the measured thrust efficiency was 45 at 1570 seconds Isp. Author