Effect of auxiliary gas injection on the operation of a Hall current plasma accelerator

Abstract

Abstract Optimization of magnetic and electric fields has been central concern for the design of a Hall current plasma accelerator since its inception decades ago. However, neutral flow dynamics in the discharge channel may have as much impact on the accelerator performance, operation stability and lifetime as the magnetic and electric fields due to its strong coupling with plasma properties. In this article, auxiliary gas injection is numerically studied for a low-power accelerator using a two-dimensional fully kinetic particle-in-cell code. Gas injection through the discharge channel sidewalls increases lifetime of the accelerator, but also degrades thrust performance suggesting that there is an optimum gas injection ratio. Although reduction in the maximum erosion rate is substantially lower than that predicted by a two-dimensional hybrid model for a high-power accelerator [14], extension of lifetime by approximately 20% appears to be possible with little impact (2%) on the thrust. The anode efficiency analysis supported by the simulated plasma properties clarifies that reduction in voltage utilization is the main cause of the observed alterations in the plasma properties and thrust performance deterioration.