Application of Mechanical Probes for Evaluation of Plasma Acceleration in Ablative PPT

In pulsed plasma thrusters (PPTs), a highly ionized plasma is created and accelerated by means of a pulsed triggered vacuum gap discharge with concurrently occurring ablation, ionization, and Lorentz-force-based acceleration of propellant. The plasma flow behavior during the PPT discharge is, therefore, highly dependent on time, space, and operation parameters. Experimental work is seen as the necessary key to further understand the processes involved and to determine future research needs. The application of mechanical probes to measure the Mach number of the plasma flow optically is discussed in this paper. Values of 1.6-3.2 were determined for a variation in time, space, and discharge voltage. An inclination of the PPT plasma flow toward the cathode was observed, which concurs with the previous research results.