Longitude Dependent Electrodynamic Effects on
Equatorial F-Region Plasma Irregularities
B. G. Fejer
Center for Atmospheric and Space Sciences, Utah State University, 4405 Old Main Hill, Logan, UT 84322-4405
Satellite and ground-based observations have shown that the occurrence of equatorial nighttime F-region plasma irregularities are strongly season and longitude dependent. The generation and evolution of these are strongly affected by the evening equatorial vertical plasma drifts during both geomagnetically quiet and disturbed times but they can also be affected by other processes. In this talk, we review the studies of the longitudinal variations of these irregularities and the physical processes proposed to explain them. Then, we discuss the possible roles of season and longitude dependent vertical and zonal plasma drifts on the generation of these irregularities during geomagnetically quiet and disturbed times.