Studies of Plasma Irregularities and Convection in the Polar Ionosphere Using HILAT, SABRE and EISCAT
Final rept. Aug 1987-31 Mar 1990,
LEICESTER UNIV (UNITED KINGDOM) DEPT OF PHYSICS
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The average ionospheric convection patterns measured by SABRE as a function of IMF Bz and By have been computed. The convection of SABRE geomagnetic latitudes about 61 to 66 N is seen to be stronger during negative Bz. Asymmetries in the convection pattern are detected as a function of By. The nightside flow reversal is found to occur at earlier local times for positive By. The duration of purely equatorward flow in this reversal region is found to be longer during intervals of negative By. Although there are only a few clear examples, the ionospheric convection associated with the morning reversal, ie. the cusp region, it also dependent upon the sign of By. A period of anomalous westward flow occurs at the higher latitudes prior to the reversal during positive By conditions. The occurrence of backscatter during the complete interval of SABRE operations was also investigated. Relating the mean daily backscatter power with various interplanetary parameters such as vBz, v-sq Bz and epsilon indicates that the sign of Bz is the most important parameter. The mean power is considerably higher during intervals of southward Bz. A study which attempted to relate the occurrence of E-region irregularities to the location of the F-region trough was undertaken. No clear relationship appears to exist between these two phenomena based upon data from SABRE and EISCAT taken over a 36 month interval. Finally, the height of the E-region irregularities measured with the SADIE system was investigated.
- Atmospheric Physics