TRAVELING CONVECTION VORTICES IN THE IONOSPHERE MAP TO THE CENTRAL PLASMA SHEET

We investigate the magnetospheric domain responsible for the generatio n of ionospheric travelling convection vortices (TCV) by comparing the location of the TCV to the locations of the low-altitude particle-pre cipitation boundaries deduced from the DMSP satellite measurements. Fo r three very well documented TCV events we are able to identify suitab le satellite passes, in the sense that for each event we can identify two to three passes occurring close to the TCV observation in both tim e and space. In all three cases the comparisons place the TCV centres at or equatorward of the central plasma sheet/boundary plasma sheet pr ecipitation boundary. Thus our results indicate that the field-alined currents related to the TCV originate in the plasma sheet rather than at the magnetopause or in the low-latitude boundary layer, as previous studies suggest.