The ionosphere response to severe geomagnetic storm in March 2015 on the base of the data from Eurasian high-middle latitudes ionosonde chain

Abstract In the paper we study the ionosphere response to the March 2015 severe geomagnetic storm according to Eurasian high-middle latitude ionosonde chain. On the basis of the ionosonde chain data we have restored the time/longitude dynamics of the high-middle latitude ionosphere over the Eurasian continent. The data showed that during the main storm phase that developed in the nighttime Siberian sector, a disturbed thermosphere region was created. This region moved westward with 50–70 m/s velocity and which was registered two-three days after the storm in the Eastern and Western Europe. Characteristics of the geomagnetic field variations showed that three active zones occurred during the storm. One is shifted from the geographic pole toward magnetic pole at ∼270° longitude. Two other zones were formed symmetrically opposite to the geomagnetic pole at longitudes ∼40° and ∼130°; the major electron density depletions at these longitudes were observed in the high-middle latitude ionosphere. On the contrary, longitudinal sector ∼80–110° showed electron density maximum in quiet conditions and fast ionosphere restoration after the storm decaying.