Detonation–deflagration one-dimensional mode transition analysis for parallel-plate plasma accelerators

Parallel-plate pulsed plasma thrusters (PPTs) and quasi-steady MPD thrusters are largely distinguished by the discrete current sheet propagation (also referred as detonation acceleration mode) and stationary steady-phase current patterns (deflagration acceleration mode), respectively. Experimental and numerical research attempts in the past have focused on showing that the two modes of operations could be explained using the same continuum process. Present work proposes a simple unified analytical energy balance model to capture this mode transition in pulsed electromagnetic thrusters. The model is tested for a high-energy PPT developed at NASA-Glenn Research Center, which operates predominantly in the quasi-steady mode. The influence of thruster geometry and circuit parameters on the mode of operation and electrical energy efficiency is analyzed. Based on the analysis of the energy transfer efficiency, it is found that operating the thruster in the quasi-steady mode improves the transfer efficiency by approximately 10 %. It is concluded that the effective electrode length, pulse timing, circuit parameters, and electrode geometry could be optimized to operate the thruster in the quasi-steady/deflagration mode, hence improving the electrical energy transfer efficiency.