Conference proceeding
Instabilities driven by ion drag: SEVENTH WORKSHOP
PHYSICS OF DUSTY PLASMAS, Vol.446, pp.157-166
AIP CONFERENCE PROCEEDINGS
01/01/1998
Abstract
When ions stream past a charged dust particle, their trajectories are deflected, resulting in the ion drag force, Fi. This force scales as the square of the particle charge, and therefore as the square of the particle diameter, in contrast to the Coulomb force QE which scales linearly with particle diameter. When the particle has a negative charge, the two forces point in opposite directions. The net force, which is the sum of these two forces, will then reverse direction at a critical particle size. In a, series of experiments, it is shown that this effect leads to an instability. Particles are grown in an rf sputtering plasma, so that their diameter and therefore charge increase with time. The dust cloud is confined by the electrostatic force QB, due to global electric fields in the discharge. As the charge grows, the confinment equilibrium abruptly becomes unstable to very-low-frequency modes, in which the dust number density is modulated. The instability begins as the 'filamentary mode', and then develops into a 'great void', which is a centimeter-size region free of dust particles. Because the plasma is a gas discharge with electron-impact ionization, this void is able to persist, due to a flow of ions originating in the center of the void, where there is a higher electron density due to the absence of electron depletion on dust.
Details
- Title: Subtitle
- Instabilities driven by ion drag: SEVENTH WORKSHOP
- Creators
- J GoreeD Samsonov
- Contributors
- M Horanyi (Editor)S Robertson (Editor)B Walch (Editor)
- Resource Type
- Conference proceeding
- Publication Details
- PHYSICS OF DUSTY PLASMAS, Vol.446, pp.157-166
- Publisher
- Amer Inst Physics
- Series
- AIP CONFERENCE PROCEEDINGS
- ISSN
- 0094-243X
- eISSN
- 1551-7616
- Number of pages
- 10
- Language
- English
- Date published
- 01/01/1998
- Academic Unit
- Physics and Astronomy; Mechanical Engineering
- Record Identifier
- 9984442200002771
Metrics
1 Record Views