1. Introduction

[2]  The morphology of quiet time F2 -layer disturbances ( Q disturbances) at middle latitudes along with general discussion of the problem has been described by Mikhailov et al. [2004] (hereinafter referred to as MDL). The revealed morphological picture turned out to be pretty complicated indicating that various processes (depending on geophysical conditions) contribute to those variations. The formation mechanism of the equatorial F2 layer is different from the midlatitude one; therefore different morphological pattern of quiet time disturbances is expected. The F2 layer at geomagnetic equator is mainly controlled by vertical EB plasma drift due to zonal electric field. The latter is known to be very variable [Fejer et al., 1991; Hari and Krishna Murthy, 1995; Namboothiri et al., 1989; Ramesh and Sastri, 1995; Scherliess and Fejer, 1999; Woodman, 1970], even under quiet conditions; therefore one may expect strong quiet time perturbations in the equatorial F2 region. Vertical plasma drifts demonstrate longitudinal variations; therefore the morphology will be considered for two equatorial stations, Huancayo (American sector) and Kodaikanal (Indian sector) separated practically by half a globe and located in the southern and northern hemispheres, respectively. This lucky situation allows one to analyze longitudinal and hemispheric differences. This paper is devoted to a morphological study of the equatorial Q disturbances along with a qualitative discussion of their possible mechanisms.