E-region wind-driven electrical coupling of patchy sporadic-E and spread-F at midlatitude
| Autor: | S. Shalimov, C. Haldoupis |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2005 |
| Předmět: | |
| Zdroj: | Annales Geophysicae, Vol 23, Pp 2095-2105 (2005) |
| Druh dokumentu: | article |
| ISSN: | 0992-7689 1432-0576 |
| DOI: | 10.5194/angeo-23-2095-2005 |
| Popis: | This paper investigates the role of neutral winds in the generation of relatively large polarization electric fields across patchy sporadic-E layers, which then map upward to the F region, to create conditions for medium-scale spread-F. The calculations are based on an analytical model that uses the current continuity equation and field-aligned current closures to the F region in order to describe quantitatively a Hall polarization process inside sporadic-E plasma patches during nighttime. In applying this model we use experimentally known values for E and F region, conductances, the ambient electric fields and prevailing neutral winds, in order to estimate the polarization fields that build up inside sporadic-E. It is found that the relatively strong west-southwest neutral winds during summer nighttime can provide the free energy for the generation of sizable polarization electric fields, which have comparable eastward and north-upward components and reach values of several mV/m. Given that the sporadic-E patches have sizes from a few to several tens of kilometers, the polarization fields can map easily to the F region bottomside where they impact ExB plasma uplifts and westward bulk motions, in line with key observational properties of medium-scale spread-F. However, the present simple model needs further development to also include wind forcing of the F region plasma and possible polarization processes inside spread-F. Keywords. Ionosphere (Electric fields and currents; Ionospheric irregularities; Mid-latitude ionosphere) |
| Databáze: | Directory of Open Access Journals |
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