ON THE PERIODIC MODULATION OF ENERGETIC ELECTRONS IN THE MAGNETOSPHERIC SKIRT REGION

Abstract

The acceleration mechanism of the energetic electrons in the magnetospheric skirt region is considered. It is inferred that the periodic modulation of these electrons is due mainly to the pulsative change of geomagnetic field lines in the skirt region, and that the cause of such periodicity is intimately connected with that of the X-ray burst, cosmic noise absorption with the periods, 4 to 6 minutes and geomagnetic pulsation, Pc-5, which are usually observed in the auroral latitudes. It is suggested that all electromagnetic disurbances are most violent at the dawn side of the skirt region compared with the other side, since the modulation mentioned above is strongest at the dawn side. As regards such disturbances, the rapid change of the geomagnetic field lines there with space and time may be most effective on the generation of energetic electrons. The acceleration mechanism of these electrons is examined in relation to the behavior of geomagnetic field lines.