Physical nature of a new cross-field current-driven instability in the lower ionosphere
| Autor: | R. N. Sudan, Ya. S. Dimant |
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| Rok vydání: | 1997 |
| Předmět: |
Physics
Atmospheric Science Ecology Paleontology Soil Science Forestry Geophysics Electron Aquatic Science Oceanography Instability Computational physics Two-stream instability Collision frequency Space and Planetary Science Geochemistry and Petrology Electric field Earth and Planetary Sciences (miscellaneous) Ionosphere Joule heating Excitation Earth-Surface Processes Water Science and Technology |
| Zdroj: | Journal of Geophysical Research: Space Physics. 102:2551-2563 |
| ISSN: | 0148-0227 |
| DOI: | 10.1029/96ja03274 |
| Popis: | The physical nature of a new instability predicted earlier in the framework of a kinetic theory [Dimant and Sudan, 1995a, b, c] is clarified by using a simple fluid model. It is associated with ohmic heating of electrons by the modulated electric field. Temperature modulations lead to the instability via two independent mechanisms. One mechanism consists in the reversal of the sign of pressure perturbations, and the other is associated with perturbations of the electron Pedersen conductivity due to the temperature dependence of the electron-neutral collision frequency. The instability gives rise to the excitation of sufficiently long waves (several meters and longer) in the upper D/lower E regions. The unstable zone covers two broad ranges of flow angles around the bisectors between the directions of the ambient electric field ±E o and the E 0 x B drift. The data available from rocket measurements in polar regions indicate possible evidence for the new instability. |
| Databáze: | OpenAIRE |
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