Spatiotemporal optical structure of plasmas in the E-to-H mode transition in an inductively coupled plasma in Ar

The change in the spatiotemporal structure of the E-to-H transition of an inductively coupled plasma in Ar is optically investigated as a function of time during the transition. Short-lived excited atoms Ar(2p₁) and Ar(2p₉) with different excitation processes have been used as optical probes. The temporal change from a capacitive to an inductive mode is demonstrated in two-dimensional real space. Different contributions of low-and high-energy electrons to the transition are discussed in terms of the integrated emission intensity from both excited atoms. The optical two-dimensional images enable us to understand the sustaining mechanism and the transition from E-to-H mode.