Forces on a small grain in the nonlinear plasma wake of another
The transverse force on a spherical charged grain lying in the plasma wake of another grain is analyzed to assess the importance of ion-drag perturbation, in addition to the wake-potential-gradient. The ion-drag perturbation is intrinsically one order smaller than the wake-potential force in the rat...
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| Format: | Article |
| Language: | en_US |
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American Physical Society
2011
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| Online Access: | http://hdl.handle.net/1721.1/65937 |
| Summary: | The transverse force on a spherical charged grain lying in the plasma wake of another grain is analyzed to assess the importance of ion-drag perturbation, in addition to the wake-potential-gradient. The ion-drag perturbation is intrinsically one order smaller than the wake-potential force in the ratio of grain size (rp) to Debye length (lambdaDe). So ion-drag perturbation is important only in nonlinear wakes. Rigorous particle-in-cell calculations of the force are performed in the nonlinear regime with two interacting grains. It is found that even for quite large grains, rp/lambdaDe=0.1, the force is dominated by the wake-potential gradient. The wake-potential structure can then help explain the preferred alignment of floating dust grains. |
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