Abstract
A miniaturised External Discharge Plasma Thruster (XPT) is developed and characterised from 50 - 250 W. The thruster performance and discharge envelope are recorded
as a function of xenon and krypton mass flow rate at various anode powers. The thrust
of the miniaturised XPT on krypton decreases by up to 35 % and the anode efficiency decreases by up to 60% for a similar anode operation. The ion current density and utilisation
efficiencies are estimated as the thruster operation is varied between xenon and krypton.
As the mini-XPT is operated on krypton the beam current remains relatively constant as
the anode power increases. At higher anode voltages the current utilisation for krypton
is noted to decrease. The plasma properties are presented as the anode power is varied
between xenon and krypton at a constant mass flow rate. The plasma potential and density
decrease by up to 35 % as the operation is varied between 0.6 mg/s of xenon and krypton. Spatial maps are presented identifying the plasma potential and density at a constant
thruster operation of 65 W and 0.6 mg/s of xenon mass flow rate. The axial electric field
distribution is presented as a function of the plasma potential and axial distance away from
the thruster.