Electric Solid Propellant Ablation in an Arc Discharge

Abstract

Electric solid propellants are advanced solid chemical rocket propellants that can be controlled (ignited, throttled, and extinguished) through the application and removal of an electric current. Electric solid propellants are also being considered for pulsed arc ablation electric thrusters, such as the pulsed plasma thruster. The focus of this work is the electrical and ablation characteristics of electric solid propellant within an arc discharge. Arc discharges of 5–20 J per pulse were created within a cylindrical cavity, and results for the electric solid propellant are compared with polytetrafluoroethylene (PTFE), which is a traditional propellant in ablative pulsed plasma thrusters. The data indicate that the electric solid propellant has higher specific ablation per pulse () relative to PTFE (), which quantitatively agrees with an ablation energy balance model. For both propellants, the equivalent circuit resistance and inductance of the plasma arc are 50 mΩ and 125 nH, respectively. Analyses are presented indicating that the physics of propellant ablation is similar for both propellants with the differences in the observed specific ablation owing to differences in the thermodynamic properties between propellants.