Equatorial F-Region Zonal Plasma Drifts Over Jicamarca During Quiet and Disturbed Conditions

F-region zonal plasma drifts are important low latitude ionospheric parameters. We use extensive incoherent scatter observations obtained at the Jicamarca Radio Observatory between 1970 and 2003 to study the characteristics of equatorial zonal plasma drifts near the F-region peak. We present initially the results of a local time, season, and solar flux dependent quiet zonal drift model which uses Bernstein polynomials as base functions. These results indicate that over Jicamarca the dependence of the nighttime eastward drift is stronger during equinox and December solstice than during June solstice. We also present the results of the first detailed study of the effect of geomagnetic activity on the zonal drifts. Our results indicate that the zonal disturbance drifts are predominantly westward with the largest values near midnight. In the post-midnight sector, these perturbation drifts are strongly solar flux dependent. The Jicamarca zonal disturbance drifts are largely accounted for by disturbance dynamo electric fields with a dominant time delay of 3-15 hours. The effects of disturbance dynamo electric field with longer time constant are restricted to the late night sector and are largest near solar maximum