Anomalous transport effects on the parallelEfield in downward auroral current regions of the Earth's magnetosphere
| Autor: | J. R. Jasperse, B. Basu, Eric J. Lund, Neil Grossbard |
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| Rok vydání: | 2011 |
| Předmět: |
Physics
Atmospheric Science Ecology Turbulence Momentum transfer Paleontology Soil Science Magnetosphere Forestry Electron Aquatic Science Oceanography Instability Magnetic field Computational physics Current sheet Geophysics Classical mechanics Space and Planetary Science Geochemistry and Petrology Electric field Physics::Space Physics Earth and Planetary Sciences (miscellaneous) Earth-Surface Processes Water Science and Technology |
| Zdroj: | Journal of Geophysical Research: Space Physics. 116 |
| ISSN: | 0148-0227 |
| DOI: | 10.1029/2010ja016314 |
| Popis: | [1] The physical processes that determine the fluid quantities and the self-consistent electric field (E∥) parallel to the magnetic field have been an unresolved problem in magnetospheric physics for over 40 years. We review a recently developed kinetic and multimoment fluid theory for inhomogeneous, nonuniformly magnetized plasma with temperature anisotropy in the guiding-center and gyrotropic approximation and apply the theory to solve for the quasi steady state in the long-range potential region of a downward Birkeland current sheet when electrostatic ion cyclotron turbulence is dominant. We find that an electron, bump-on-tail-driven ion cyclotron instability produces the turbulence and that a large enhancement in ∣E∥∣ by nearly a factor of 40 occurs when the turbulence is present compared to the case when it is absent. Anomalous momentum transfer (anomalous resistivity) by itself has a very small effect on E∥; however, the presence of the turbulence and the anomalous energy transfers (anomalous heating and cooling) that result have a very large effect on the entire solution. In the electron and ion momentum balance equations for E∥, the turbulence enhances the magnitude of E∥ by reducing the effect of the generalized parallel pressure gradients and thereby enhancing the effect of the mirror forces. A new, nonlinear formula for the current-voltage relationship in downward Birkeland current regions is also given. |
| Databáze: | OpenAIRE |
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