VARIABILITY OF DAYSIDE CONVECTION AND MOTIONS OF THE CUSP CLEFT AURORA

We present measurements of the ionospheric plasma flow over the range of invariant latitudes 71-76-degrees, observed at 10-second resolution using both the EISCAT radars, with simultaneous observations of the 6 30 nm cusp/cleft aurora made by a meridian-scanning photometer at Ny A lesund, Svalbard. A major increase in the trans-auroral voltage from 5 to 40 kV (associated with sunward convection in the early afternoon s ector) is found to follow a southward motion of the aurora and coincid e with the onset of regular transient auroral breakup events. It is sh own that these observations are consistent with recent theoretical wor k on how ionospheric flows are excited by time-dependent reconnection at the dayside magnetopause.