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Accueil > Séminaires & Soutenances > Séminaires, soutenances de thèses et HDR précédents > 2009 > Séminaires 2009 > Le jeudi 24 septembre à 11h

Le jeudi 24 septembre à 11h

Michael Lieberman (Electrical Engineering and Computer Science Department, University of California, Berkeley)

Adventures in 2D PIC Simulations of Electronegative Discharges : (1) Double Layer Formation ; (2) Transport in Magnetized Discharges

le jeudi 24 septembre à 11h à Palaiseau, salle de réunion du CPHT

Two-dimensional (2D) particle-in-cell (PIC) simulations of low temperature electronegative (EN) discharges were conducted in two system geometries : (1) The formation of double layers (DL’s) was studied in a two-region system with rescaled oxygen cross sections. The DL’s form near the junction between a small source (heating) section connected to a larger downstream section, for pressures of 1–24 mTorr. A 1D double-layer model coupled with global particle and energy balances was developed. Time-varying wave phenomena coexisting with the DL were also observed. (2) The transport of positive ions, negative ions, and electrons was studied in a 20 mTorr magnetized oxygen-like discharge in rectangular geometry with approximately uniform electron temperature. A finite flux of electrons to the transverse wall was always observed. A 1D (transverse) model was developed, which mimics the axial wall losses by introducing a bulk loss frequency. PIC simulations were also performed using iodine-like cross sections with a hotter electron core connected to cooler transverse edge regions. The transverse electron losses were strongly reduced. A hot core/cold edge model was developed. For both system geometries, the PIC diagnostics allow the calculation of various plasma parameters, not easily measured in experiments, to be compared easily to the analytical models.

CNRS Ecole Polytechnique Sorbonne Université Université Paris-Saclay Observatoire de Paris
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Mentions légales
Exploitant du site : Laboratoire de Physique des Plasmas, Ecole Polytechnique route de Saclay F-91128 PALAISEAU CEDEX
Hébergeur : Laboratoire de Physique des Plasmas, Ecole Polytechnique route de Saclay F-91128 PALAISEAU CEDEX
Directeur de la publication : Dominique Fontaine (Directrice)