A study on pulsed hydrogen plasma stream to understand the contributing factors for heat energy density in static pressure

A Pulsed Plasma Accelerator (PPA) is a unique system capable of generating a high-speed, high-density transient plasma stream with a high heat energy density. This makes it suitable for different applications including material processing, plasma matter interaction (PMI), simulation astrophysical events, or as a plasma thruster based on the characteristic behavior of the plasma stream. The heat energy density is one of the important parameters for evaluating the efficient use of PPA in fusion-relevant PMI studies. It is believed that the heat energy to be delivered by a plasma stream of this nature is a result of the integrated thermalized contribution of multiple energy-transfer channels associated with the stream. The maximum calorimetric heat energy density was found to be ∼0.2 MJ/m2 at a discharge voltage of 14 kV and a static pressure of 2 mbar. This heat energy density is comparable to the heat load imparted to plasma-facing materials during edge-localized modes, and the periodic outburst of particles observed during H-mode confinement of plasma in fusion reactors, typically ranging from 0.2 to 3 MJ/m2 within pulse durations of ∼0.1–0.5 ms. The results suggest that, under the specific experimental conditions of this study, shock-induced thermalization is the dominant mechanism that governs heat energy deposition in the static mode of the PPA.