The storm time ionosphere dynamics at low solar activity period

At the boundary of the 23rd and 24th solar cycles the geomagnetic disturbances occurred on October 11, 2008, July 22, 2009, May 2 and 29, 2010 caused the most appreciable ionosphere reaction. The peculiarities of spatial-temporal ionospheric response over the Europe are investigated. The results of multi-instrumental radiophysical observations were used for analysis. Each of considered geomagnetic disturbances with the similar magnitude caused the ionospheric response with different duration, amplitude, sign, and spatial character. It was observed positive, two-phase and negative ionospheric storms. The mechanisms of positive ionospheric storms caused by the moderate geomagnetic disturbances were considered.