RF Source Modifications to Improve Performance of an Electronegative Plasma Thruster

In traditional gridded electrostatic ion thrusters, positively charged ions are generated from a plasma discharge of noble gas propellant and accelerated to provide thrust. A separate electron source, typically a neutralizer cathode that consumes propellant, is required in the propulsion system to neutralize the ion beam after it exits the thruster, thereby maintaining overall charge balance. However, if high-electronegativity propellant gases are used, a plasma discharge can result that consists of both positive and negative ions. Such an electronegative plasma thruster has the ability to generate thrust with a quasi-neutral ion-ion plume, thus allowing for the elimination of the neutralizer cathode subsystem, reduction of propulsion system complexity, and improvement of system lifetime and operational flexibility.