Jena 2013 – scientific programme
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P: Fachverband Plasmaphysik
P 22: Niedertemperaturplasmen II
P 22.1: Invited Talk
Friday, March 1, 2013, 09:45–10:15, HS 2
Physical processes in the afterglow of pulsed low-pressure discharges in argon — •Tsanko V. Tsankov1, Yusuf Celik1, Dirk Luggenhölscher1, Uwe Czarnetzki1, Mitsutoshi Aramaki2, and Shinji Yoshimura3 — 1Institute for Plasma and Atomic Physics, Ruhr-University Bochum, 44780 Germany — 2Department of Electrical Engineering and Computer Science, Nagoya University, 464-8603, Japan — 3National Institute for Fusion Science, Toki 509-5292, Japan
In this talk a description of the key processes in argon low-pressure afterglows will be presented which forms a unified picture of the afterglow physics [1]. The leading process is the effective electron energy loss through evaporative cooling, i.e. escape of only the most energetic electrons to the walls. On the same time scale quenching of the metastable atoms occurs. At later times the evaporative cooling is adiabatically balanced by Coulomb collisions with the ions. The established low electron temperature enhances the three-body recombination process which leads to population of Rydberg atomic levels. Through de-excitation collisions with electrons and radiative transitions electrons in Rydberg states decay to lower states and eventually end up in the metastable states. In consequence, metastable atoms are initially almost totally lost due to quenching and are recreated later by recombination. Finally, they are lost again by diffusion and energy pooling collisions. Results from measurements, analytical models and numerical simulations will be presented and compared.
[1] Y. Celik, Ts. V. Tsankov, M. Aramaki, S. Yoshimura, D. Luggenhölscher, U. Czarnetzki, Phys. Rev. E 85, (2012) 046407; ibid. 056401