Hydrodynamic-based measurements of energy deposition in atmospheric pressure plasma jets

Time-resolved gas density and temperature of atmospheric pressure plasma jets were measured using a recently developed dual-frame interferometry (DFI) diagnostic [1]. This diagnostic is capable of resolving the dynamics of weak shock waves generated by short, repetitive electric discharges in an atmospheric pressure plasma jet. The measured parameters—shock wave velocity and amplitude—were fitted to a hydrodynamic simulation to calculate energy deposition and the resulting gas heating. The calculated gas temperature agrees with previously obtained optical emission spectroscopy measurements of nitrogen vibrational temperature. DFI provides a non-spectroscopic approach to estimating the energy deposited into the gas by guided streamers. The deviation between experimental and simulation results near the gas flow axis highlights the importance of the repetitive nature of energy deposition and requires further investigation.