2-DIMENSIONAL HIGH-RESOLUTION IMAGING OF THE EQUATORIAL PLASMA FOUNTAIN

The first visual representation of the reverse equatorial plasma fount ain during night-time has been made using images obtained by an All Sk y Imaging Fabry Perot Spectrometer observing the OI 630.0 nm airglow e mission line from the thermosphere; the intensity of this line emissio n is directly related to the F-region plasma densities during night-ti me. From the identifiable features when the enhanced airglow emitting region moves overhead and when it completely leaves the field-of-view, the equatorwards velocity of the EIA has been estimated to be approxi mately 150 km/h at the latitude of the measurements (Mt Abu, 20-degree s 20' dip latitude, India). Lower limits for the latitudinal and longi tudinal extents of the EIA crest have each been inferred to be 6-degre es.