ИСТИНА

Previous studies using the METEOR-M1 satellite have shown that the equatorial boundary of the auroral oval is often located equatorward from the footprint of the polar boundary of the outer electron radiation belt, and the number of such events increases with both AE and PC indexes. We continued this study using data from TED and MEPED instrumentation onboard POES satellites to determine how the position of the auroral oval varies respectively to the position of energetic electron fluxes during isolated geomagnetic substorms. This study covers substorms with minimum value of AL index ranging between -300 and -1200 nT. For the same events, we also used the data of DMSP, THEMIS, and Van Allen Probe satellites. This allowed us to see as well the behavior of plasma pressure and to precise the location of the outer electron radiation belt versus the auroral oval. It was found that there are strong evidences that the substorm expansion phase onsets for isolated substorms are located equatorward from the polar boundary of the electron radiation belt.