Transition from electrostatic-to-electromagnetic mode in a radio-frequency Ar inductively coupled plasma in atmospheric pressure

Abstract

The dynamics of mode transition from the electrostatic (E) to electromagnetic (H) mode of a radio-frequency argon inductively coupled plasma (ICP) in atmospheric pressure is investigated, both experimentally and theoretically. High-speed (4500 f/s) camera imaging is performed to investigate the dynamics of E–H discharge mode transition. The temporal plasma loading impedance of Ar inductive discharges at the E–H transition stage is also observed to investigate the transition dynamics. The experimental observations reveal that the formation of the multiple streamerlike electrostatic discharge paths followed by the strong ring-shaped azimuthal discharges leads to ignite the high-pressure (around 1 atm or more) ICPs. The time scale of E–H discharge mode transition is estimated by using proposed models and the estimated results are compared with that of the experimental one. It is found that the estimated results agree well with that of the experimental one.