Kiel 2011 – wissenschaftliches Programm

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P: Fachverband Plasmaphysik

P 20: Simulationsverfahren / Theorie/Modellierung II

P 20.5: Vortrag

Donnerstag, 31. März 2011, 12:00–12:15, HS H

Evaporation cooling of electrons in the argon afterglow — •Tsanko Tsankov¹, Yusuf Celik¹, Dirk Luggenhölscher¹, Uwe Czarnetzki¹, and Mitsutoshi Aramaki² — ¹Institute for Plasma and Atomic Physics, Ruhr-University Bochum, 44780 Germany — ²Department of Electrical Engineering and Computer Science, Nagoya University, 464-8603, Japan

In various investigations of the afterglow of noble gas plasmas effective cooling by “evaporation” of hot electrons across the boundary sheath potential has been identified. In our recent experiments on the afterglow of a planar ICP discharge in Argon at low pressure (1 Pa) enhanced recombination indicates electron temperatures in the range of 0.1 eV. Cooling has been verified experimentally by measurements of the decay of the ion energy at the wall. A 2D fluid-dynamic simulation and an analytical model are in good agreement and identify clearly “evaporation cooling” as the dominant effect. The time scale of the effect is obtained to be of the order of 10 µs, well in agreement with the experimental results.