Storm sudden commencements in geomagnetic H, y and Z fields at the equatorial electrojet station, Annamalainagar

Abstract

The signature of storm sudden commencements at the Equatorial Electrojet Station, Annamalainagar, are shown to consist of a positive impulse in horizontal field, H, and a negative impulse in eastward field, Y, in the same manner as the solar flare effect (sfe) at the same station. The signature of SSC in the vertical component consists of a positive impulse, opposite to the sfe impulse in Z. The amplitudes of SSC impulse in H and Y indicate a maximum around midday suggesting an equatorial electrojet effect on these. The SSC effects on the eastward field (Y) at equatorial electrojet stations consist of a global part due to the compression of the magnetosphere and another a localised effect due to the electric field communicated from the interaction of the solar wind with the interplanetary magnetic field Bz component to the equatorial latitudes.