Observation of an abrupt electron heating mode transition in capacitive single radio frequency discharges
Sebastian Wilczek, Jan Trieschmann, Julian Schulze, Ralf Peter Brinkmann, Thomas Mussenbrock, Aranka Derzsi, Ihor Korolov, Zoltan Donko
66th Annual Gaseous Electronics Conference (GEC), Princeton (New Jersey), USA, 30 September - 04 October (oral contribution)
The electron heating in capacitive discharges at very low pressures (=1 Pa) is dominated by stochastic heating. In this regime electrons are accelerated by the oscillating sheaths, traverse through the plasma bulk and interact with the opposite sheath. By varying the driving frequency or the gap size of the discharge, energetic electrons reach the sheath edge at different temporal phases, i.e., the collapsing or expanding phase, or the moment of minimum sheath width. This work reports numerical experiments based on Particle-In-Cell simulations which show that at certain frequencies the discharge switches abruptly from a low density mode in a high density mode. The inverse transition is also abrupt, but shows a significant hysteresis. This behavior is explained by the complex interaction of the bulk and the sheath.
This work is supported by the German Research Foundation in the frame of TRR 87.