The electron forewake: Shadowing and drift-energization as flowing magnetized plasma encounters an obstacle
- Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)
Flow of magnetized plasma past an obstacle creates a traditional wake, but also a forewake region arising from shadowing of electrons. The electron forewakes resulting from supersonic flows past insulating and floating-potential obstacles are explored with 2D electrostatic particle-in-cell simulations, using a physical ion to electron mass ratio. Drift-energization is discovered to give rise to modifications to the electron velocity-distribution, including a slope-reversal, providing a novel drive of forewake instability. The slope-reversal is present at certain locations in all the simulations, and appears to be quite robustly generated. Wings of enhanced electron density are observed in some of the simulations, also associated with drift-energization. In the simulations with a floating-potential obstacle, the specific potential structure behind that obstacle allows fast electrons to cross the wake, giving rise to a more traditional shadowing-driven two-stream instability. Fluctuations associated with such instability are observed in the simulations, but this instability-mechanism is expected to be more sensitive to the plasma parameters than that associated with the slope-reversal.
- OSTI ID:
- 22486413
- Journal Information:
- Physics of Plasmas, Vol. 22, Issue 10; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
Fore-wake excitations from moving charged objects in a complex plasma
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journal | October 2016 |
Wake effects of a stationary charged grain in streaming magnetized ions
|
journal | August 2018 |
| Wake effects of a stationary charged grain in streaming magnetized ions | text | January 2018 |
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