Electric fields and currents in the equatorial E-region over American and Indian zones - A comparison

Abstract

E-region electric fields estimated from VHF radar observation of the phase velocity of plasma irregularities and the strength of overhead currents estimated from ground level geomagnetic field measurements at two equatorial stations, Jicamarca, Peru and Thumba, India, are compared. The overhead currents in the equatorial regions are driven by electric fields mapped from nonequatorial latitudes, where they are generated by the dynamo action. The geomagnetic declination angle at a given place thus plays an important role in determining the daytime variation of electric fields in the equatorial E-region, which in tum influences the vertical distribution of the overhead currents. The geomagnetic declination angle at Jicamarca being much larger than at Thumba, the present comparative study clearly brings out the role of geomagnetic declination angle in determining the vertical distribution of daytime currents in the equatorial E-region.