ИСТИНА

The role of solar wind pressure and interplanetary magnetic field variations in the outer Earth`s radiation belt dynamics is under consideration during the last decades. Unfortunately, the physical mechanisms that control the loss and acceleration of the magnetospheric relativistic electron fluxes are not evident until now. In this study we compared and contrasted some features of relativistic electron flux dynamics during two largest geomagnetic storms in 2015 (17-18 March and 22-23 June) having the similar Dst-variations profiles and amplitudes (~200 nT) but accompanied by different conditions in the interplanetary space. Analysis of experimental data from Van Allen Probes (RBSP), GOES, Electro-L, POES, Meteor-M, SAC-D and Jason-2 satellites was combined with magnetic field measurements on-board RBSP satellites and calculations on the base of the A2000 model of the magnetosphere. Multipoint observations at GEO and LEO show the dramatic changes in the MeV electron populations during the main phase of the magnetic storms. We have found that solar wind and IMF variations are responsible for large-scale magnetospheric current system changes that reveal themselves in the different dynamics of the relativistic electron fluxes during two major storms occurring in 2015.