Model of an electrothermal pulsed plasma thruster

The physical processes of a pulsed discharge in a dielectric (Teflon(R)) cavity of a coaxial electrothermal pulsed plasma thruster (PPT) are analyzed. The considered PPT has this central Teflon cavity to produce a high-pressure cloud of ablation products during the discharge pulse. The mathematical model includes the Teflon thermal conduction, the plasma energy balance, the mass and momentum conservation in a quasi-neutral plasma region, and the relation between the plasma parameters in a nonequilibrium layer near the ablated Teflon surface. It is found that the plasma parameter variation along the cavity length is an important feature of the ablation-controlled discharge in the cavity that affects the plasma energy balance, mass and momentum conservation, and thermal conductivity. Performance characteristics of the PPT such as mass ablation and impulse thrust bit are calculated. Predicted plasma temperature, ablation rate, and gasdynamic thrust are found to be in agreement with experimental data.