Darmstadt 2008 – wissenschaftliches Programm
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P: Fachverband Plasmaphysik
P 8: Staubige Plasmen/Plasma-Wand-Wechselwirkung II
P 8.7: Vortrag
Donnerstag, 13. März 2008, 10:00–10:15, 2E
Microscopic calculation of the charge of a dust particle in a plasma — •Franz Xaver Bronold1, Holger Fehske1, Holger Kersten2, and Hans Deutsch1 — 1EMA Universität Greifswald, 17489 Greifswald, Deutschland — 2CA Universität zu Kiel, 24098 Kiel, Deutschland
We calculate, from a genuine microscopic point of view, the quasi-stationary charge of an isolated dust particle confined in a low-temperature gas discharge. In contrast to the ambipolarity condition, which balances the total electron with the total ion flux, we obtain the charge from the quasi-stationarity of the electron and ion surface densities. Our approach suggests (i) that the charge results from the balance of electron charging with electron desorption and (ii) that ions affect the charge primarily through the temperature of the dust particle, which depends on the ion bombardment. Using orbital-motion limited fluxes and the neutral gas temperature as an adjustable parameter, we obtain excellent agreement with experimental data for a variety of discharges.
Support from the SFB-TR 24 ``Complex Plasmas'' is greatly acknowledged. F. X. B. acknowledges special funding 0770/461.01 by the state Mecklenburg-Vorpommern.