Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation
Russian Academy of Sciences
( founded in 1939 )
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   Grant of RFBR #97-05-64085   Grant of RFBR #01-02-64155   

The RFBR grant 01-05-64155 "Reconstruction of the global (three-dimensional) response of the ionosphere to a strong magnetospheric disturbance" is now fulfilling. The project goal is the investigation of the global storm-time variations of electron density and temperature and dynamics of the topside ionosphere structure (day-side cusp, auroral oval, main ionospheric trough, ring ionospheric trough, subauroral Te peak and equatorial anomaly).

The first results obtained in this field are the following. The background Ne distribution at the height of ~430 km for the quiet night-time equinoctial conditions from the Cosmos-900 data is constructed and investigated - Fig.5.

On the basis of exact knowledge of the background the global response of the ionosphere in Ne to the March 22-23, 1979 magnetic storm was isolated from Intercosmos-19, Cosmos-900 and ground-based data. For example the global storm-time variations of Ne in the night-time ionosphere are show on Fig.6. The basic features of the ionospheric storm were investigated including the storm positive phase in Ne associated with the Bz northward turning and its negative phase caused by IGW passage after the AE-index burst. From the Intercosmos-19 and Cosmos-900 data the equatorial boundary of the auroral diffuse precipitation, DPB and main ionospheric trough, MIT dynamics was studied. It was shown that the MIT and DPB positions were controlled by DR-index with the correlation factor r = 0.95. The negative disturbance in Ne at latitudes near 56-57 degrees is connected with the so called ring ionospheric trough, RIT. The background Te distribution for the day-time quiet equinox conditions was also constructed - Fig.7. On the basis of exact knowledge of the background the disturbed Te variations were isolated for March 22-23, 1979 magnetic storm. Its basic characteristics were revealed, in particular, variation of the day-time cusp position and the equatorial anomaly dynamics were studied.