Transient striations in an inductively coupled plasma during E-to-H transitions

Azimuthal transient striations are reported for inductively coupled Ar plasma during E-to-H transition at 200 mTorr. In this transient process, the number of striations increases with time, and striations ultimately disappear when the H mode is reached. An integrated model is developed to investigate the mechanism of this phenomenon. This integrated model incorporates a one-dimensional time-dependent fluid model with a perturbation analysis, as well as a circuit model for power coupling with the external radio-frequency driving source. Based on this integrated model, the development of striations is proposed to be a consequence of ionization instability due to the variation in the electron energy distribution function. The model results for the temporal evolution of the number of striations are in good agreement with the observed data.