Turbulence in plasma confined by a magnetic dipole is dominated by interchange fluctuations with complex dynamics and short spatial coherence. We report the first use of local current-collection feedback to modify, amplify, and suppress these fluctuations. The spatial extent of turbulence regulation is limited to a correlation length near the collector. Changing the gain and phase of collection results in power either extracted from or injected into the turbulence. This mechanism is analogous to the magnetospheric-ionospheric coupling by field-aligned currents. The measured plasma response shows some agreement with calculations of the linear response of global interchange-like MHD and entropy modes to current-collection feedback.
| Identifer | oai:union.ndltd.org:columbia.edu/oai:academiccommons.columbia.edu:10.7916/D8GT5M4S |
| Date | January 2015 |
| Creators | Roberts, Thomas Maximillian |
| Source Sets | Columbia University |
| Language | English |
| Detected Language | English |
| Type | Theses |
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