Longitudinal inequalities in equatorial ionosphere electric field

Abstract

The daily, seasonal and solar cycle variations of the horizontal component of geomagnetic field (<img src='/image/spc_char/delta.gif' border=0><i>H</i>) show significant difference over equatorial stations in the Indian and the American sectors. The electric field parameter <img src='/image/spc_char/delta.gif' border=0><i>H/N_m</i>E [obtained by normalizing <img src='/image/spc_char/delta.gif' border=0><i>H</i> by the peak electron density in the E region (<i>N_m</i>E)] increased by 15% over the Indian sector and by 26% over the American sector from minimum to maximum solar activity years. Seasonal variation of the electric field parameters show significant equinoxial maxima in both the Indian as well as the American sectors. Daily variation of <img src='/image/spc_char/delta.gif' border=0><i>H/N_m</i>E in the American sector has shown an asymmetry in electric field with respect to noon, with significant larger values in the forenoon than in the afternoon hours. Values of <i>H</i> over American stations show a continuous increase with time during the post-midnight hours leading to a significant positive value of <img src='/image/spc_char/delta.gif' border=0><i>H</i> at sunrise