Different behaviors of outer radiation belt keV and MeV electrons during two sequential geomagnetic storms

Electron flux dropout is an extraordinary phenomenon in the outer radiation belt, which is characterized by the drastic depletion of trapped electron populations over a broad range of energies, pitch angles, and L-shells. Using data from multiple satellites, we study a 5-day dropout of MeV electrons at the edge of outer radiation belt during two sequential geomagnetic storms of similar magnitude under lightly disturbed solar wind conditions. Phase space density analysis show that radial outward diffusion was the main reason for the dropout. However, during these two sequential geomagnetic storms, keV electrons behaved differently from MeV electrons. MeV electrons can maintain dropouts up to almost five days, whereas keV electron dropouts just lasted for a few hours. Furthermore, the location of maximum flux of MeV electrons in the outer radiation belt showed an inward movement during this period, while the peak flux location of keV electrons showed an outward moving trend. By analyzing the data of multiple satellites, the differences have been explained in more detail.