Vacuum arc thruster
A vacuum arc thruster is a form of Electrically [powered spacecraft propulsion|electric spacecraft propulsion]. It uses a vacuum arc discharge, across an insulator, between two electrodes to produce thrust. A metal plasma is produced from micrometer-size cathodic spots. Thus, whereas the insulator is used as propellant in a pulsed plasma thruster, in a VAT the metallic cathode is consumed as propellant.