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P: Fachverband Plasmaphysik
P 4: Staubige Plasmen
P 4.3: Vortrag
Montag, 30. März 2009, 17:10–17:25, HS Biochemie (groß)
Charging and drag force on a static spherical dust grain immersed in rf discharges — •VenkataRamana Ikkurthi1, Konstantin Matyash2, Andre Melzer1, and Ralf Schneider2 — 1Ernst-Moritz-Arndt Universitat Greifswald, 17489 Greifswald, Germany. — 2Max-Planck Institut fur Plasmaphysik, EURATOM Association, 17491 Greifswald, Germany.
Dust charge, potential and ion drag force on static spherical dust grains located in an argon rf discharge under typical laboratory experiment conditions have been computed using a three-dimensional Particle-Particle-Particle-Mesh code. Our model allows to self-consistently resolve the electrostatic sheath in front of a wall. The MD region around the dust grain allows to resolve the dust-plasma species interactions. Elastic and inelastic collisions have been included in the current model to obtain realistic rf discharge plasma conditions. Dust charge, potential, potential distribution around the dust and ion drag force on the dust have been computed for various sizes of dust placed at different locations in the rf discharge. The dust charge is found to be less negative than the values from simple Orbit Motion Limited model due to ion-neutral collisions. The dust potential is found to be increasing with dust size. The shielding length of the dust is obtained between electron and ion Debye lengths. The drag force is found to increase nonlinearly with the dust size. The effect of collisions is to increase the ion flux to the dust grain resulting in an increase of the drag force. These studies have been extended for two static spherical dust grains located in the rf discharge and results will be presented.