Plasma discharge modes in a 30 kW DC air arc-jet: an experimental and theoretical study

The 30 kW mARC II is a non-magnetic segmented-constrictor disk arc-jet facility used to generate high-enthalpy conditions for the development of low-maturity aerothermal technologies. In this work, air is injected around the button-shaped cathode using a swirl geometry. The gap between the electrodes is modulated using two arc-heater configurations: "2+0" and "3+1", where the first digit indicates the number of disks between the cathode and anode, and the second digit indicates the number of disks between the anode and a convergent-divergent nozzle. In this work, we analyze experimental data and theory to identify and infer which plasma discharge modes are present during mARC II operation.