Diagnostics and Exploration of Current Sheet Formation in the High-Pulse-Rate Pulsed Inductive Thruster (HiPeR-PIT)

Abstract

Experimental measurements and numerical modeling of plasma current sheets in a newdesign for an Inductive Pulsed Plasma Thruster (IPPT) are presented. The High-Pulse- Rate Pulsed Inductive Thruster (HiPeR-PIT), is a low energy (∼3.8 J), planar coil, electrical propulsion concept employing a two-turn Archimedes spiral acceleration coil, and two stages of propellant pre-ionization, RF plasma discharge for the first stage, and a high frequency energy pulse through the acceleration coil for the second. Current sheet parameters were measured through the use of optical diagnostics and through an Electric field probe, B-dot probe, and Rogowski coil. Current sheet visualization from the optical diagnostics provided an estimated peak sheet velocity of ∼25 km/s. Several studies were performed to identify the ideal operating conditions of the thruster by varying the voltage of the main bank, varying the capacitance of the main bank, and varying the background gas pressure. Experimental results were compared to a one-dimensional numerical model. Results of the experiment matched the general trends from the numerical model initially, but diverged from the model in later simulation times. Results from both the numerical and experimental studies indicated potential advancement paths for the development of the HiPeR-PIT. Future improvements include increasing the chamber background pressure, increasing the energy per pulse, and adjusting the pre-ionization scheme to ensure uniform distribution of the pre-ionized gas.