Self-organization of touching-target current with ac voltage in atmospheric pressure plasma jet for medical application parameters

In experiments with the cold atmospheric pressure plasma jet, the frequency of the current measured near the treated target shows a mismatch with the voltage frequency. The system including the plasma device and target organizes the plasma delivery differently with changing voltage frequency and amplitude. All electromagnetic and chemical processes near the target depend on the frequency of the plasma-target contacts. In experiments and in 2D fluid model simulations, the self-organization of touching-target current is studied for voltage frequencies of 10-50 kHz and amplitudes of 2.5-6 kV. The streamer propagation through the volumetric plasma cloud outside of discharge device and the mechanism responsible for variation of touching-target current frequency are discussed.