Stuttgart 2012 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

P: Fachverband Plasmaphysik

P 9: Simulationsverfahren/Theorie/Modellierung

P 9.7: Vortrag

Dienstag, 13. März 2012, 16:05–16:20, V57.01

Ionization by drift and ambipolar electric fields in electronegative capacitive radio frequency plasmas — •Julian Schulze¹, Aranka Derzsi², Kristian Dittmann³, Torben Hemke¹, Jürgen Meichsner³, Zoltan Donko², and Uwe Czarnetzki¹ — ¹Ruhr-University Bochum — ²Hungarian Academy of Sciences — ³University of Greifswald

Electron heating dynamics in strongly electronegative CF4 capacitive radio frequency discharges is investigated by kinetic particle simulations, experimental phase-resolved optical emission spectroscopy, and an analytical model [1]. Unlike α- and γ-mode operation, electrons accelerated by strong drift and ambipolar electric fields in the plasma bulk and at the sheath edges are found to dominate the ionization in such electronegative plasmas under distinct conditions. These fields are caused by a low bulk conductivity and local maxima of the electron density at the sheath edges, respectively. Mode transitions from this novel Drift-Ambipolar (DA) heating mode into classical heating modes are induced by voltage and pressure variations. Analogies to microscopic atmospheric pressure plasma jets and consequences of the discharge operation in the DA mode on the Electrical Asymmetry Effect are discussed [2].

[1] J. Schulze et al. (2011) Phys. Rev. Lett. accepted for publication [2] J. Schulze et al. (2011) Plasma Sourc. Sci. Technol. 20 045008