Formation of the Outer Radiation Belt during Geomagnetic Storms and the Adiabatic Mechanism of the Rise and Fall of Relativistic Electron Fluxes

An analysis is performed for data from the Russian METEOR-M2 spacecraft and the RBSP/Van Allen probes received during several magnetic storms with D st < –100 nT. The high latitude trapping boundary of electrons with energies >100 keV is shown to be localized inside the region of auroral precipitations and sometimes coincides with the polar boundary of an auroral oval. The contribution from the adiabatic effect to the drops in relativistic electron fluxes during the main phase of a storm and their growth during the recovery phase is determined.