Optimization of discharge triggering in micro-cathode vacuum arc thruster for CubeSats

The ignition and optimization of the pulsed micro-cathode triggerless vacuum arc thruster model are analyzed. To this end a simplified model of the thruster consisting of two rectangular electrodes on an alumina ceramic plate with a variable inter-electrode gap covered by a conductive film of carbon paint is considered. It is shown that after optimizing the inter-electrode gap, the electrical power and the value of the magnetic field parallel to the film surface, such an `idealized' thruster model can provide up to 1.2-1.3 million pulses with a high degree of stability of ignition and a large amplitude of arc current. These findings may be used in designing long-life and durable low-power micro-cathode thrusters with rigidly fixed, unmovable electrodes. We also propose the concept of a modular thruster consisting of separate elementary consumable thrusters-the modular thruster lifetime increases with the number of these elementary thrusters.