Ionospheric disturbances during 17–19 March 2015 magnetic storm over Northern Region of Russia

Based on data from the Yekaterinburg radar (YeKB radar), ionospheric stations, located within the radar field of view and 20° eastward of it, as well as from 7 radio paths passing through the region under consideration a complex analysis of ionospheric disturbances during the 17-19 March 2015 magnetic storm have been done. By analyzing data from YeKB radar, vertical and oblique-incidence sounding ionograms, we found that on 17 March during the main and early recovery storm phases, the major contribution to the development of the ionospheric disturbances, observed at corrected geomagnetic latitudes 53-70°, was made by impact ionization of the ionosphere by precipitating magnetospheric particles. It had lead to an increase of foF2 at the stations of vertical sounding, and the appearance of diffuse reflections from the E and F regions and later, intense sporadic layers, alternating with intervals of total absorption as can be seen from riometric data. The main features of this magnetic storm were the large latitude width of auroral precipitation zone and its shifting to equator to geographic latitude ~ 50°. It could be connected with the high variability of interplanetary magnetic field and solar wind impacted on the magnetosphere. During the recovery phase of the storm in the morning at the stations of vertical sounding was recorded only sporadic layers. In daytime values of critical frequency and maximal observed frequency were less then the background values by a factor of 2. Such decreasing was observed in total electron content (TEC) data. Therefore, a simultaneous contraction of the electron density maximum in F-region and reduce of TEC may be due to common cause and the related change in the composition of the neutral atmosphere.