Numerical analysis on ionization characteristics in pulsed plasma thruster discharge

Ionization process of propellant ablation products plays a vital role in pulsed plasma thruster (PPT). Its effects on plasma generation and behaviors directly determine the PPT performances. To accurately describe the ionization characteristics in PPT discharge, a dynamic coupling model of ablating boundary layer and plasma layer was presented on the basis of thermochemical reaction. Numerical solutions of LES-6 PPT using this model were studied, and the ablation process of PTFE excited by current pulses and the temporal and spatial variation of the different plasma species in the discharge channel were revealed. It is found that plasma is mainly composed of monovalent ions, of which carbon ions and fluorine ions are focused on the upstream and downstream discharge chamber, respectively. A large number of short-lived and highly ionized (divalent and trivalent ions) carbon and fluorine species are created in initial stage, and results of peak time of the various plasma species show a good agreement with plume experimental data. It is valuable for theoretically studying the discharge energy distribution and loss mechanism in PPT.