ИСТИНА

An analysis of case events and statistics of positive ionospheric storms in the dayside region of equatorial ionization anomaly was performed in relation to recurrent magnetic storms (RMSs) that dominate in geomagnetic and ionospheric conditions on the declining phase of solar activity since 2004 until 2008. It was shown that total electron content (TEC) has a tendency to decrease in the beginning of RMSs and enhance few days after, in the maximum and in the recovery phase of RMSs, during intense long-duration continuous auroral activity produced by high-speed solar wind streams. The response of positive ionospheric storms to solar, heliospheric and geomagnetic drivers reveals a prominent longitudinal and seasonal asymmetry. In the longitudinal range from –90° to 90°, the solar illumination plays the most important role, and in the range from –120° to 90°, the influence of heliospheric and geomagnetic drivers becomes significant. The highest correlations of the TEC enhancements with the heliospheric and geomagnetic drivers have been found during the winter season. Possible mechanisms of the RMS-related ionospheric storms are discussed.