Study of Earth and Jupiter-like plasmas for atmospheric entries using a non-transferred arc torch

This paper presents the results obtained by a 100 kW non-transferred arc plasma torch dedicated to the studies of plasmas characteristics of atmospheric entries of spatial probes, especially Earth and Jupiter entries. Spectra acquisition of the produced plasmas is achieved using optical emission spectroscopy. For Earth entry conditions, air plasma was obtained with a maximal temperature around 6800 K with a good agreement using atomic lines of oxygen and nitrogen (and also copper coming from electrode's ablation) and molecular bands of N2, CN and $\text{N}_{2}^{+}$ , testifying to a good thermal equilibrium. As the first step in the study of Jupiter atmospheric entry, pure helium plasma was produced with the same maximal temperature of about 7500 K. Helium plasma was achieved for the first time using the plasma torch. Recorded spectra show a continuum, He I lines as well as copper. He II lines are not detected.