Initial EISCAT observations of plasma convection at invariant latitudes 70°–77°

Abstract The potential of the EISCAT radar system for observing plasma convection patterns at high latitudes has been explored in a preliminary experiment on 27 November 1982. Using a beamswinging technique, plasma velocity was measured at slant ranges of 645–1170 km, enabling velocity vectors to be derived for invariant latitudes 70°–77°. Although operational problems limited the experiment to 80 min, some interesting observations of high-latitude flows were made. Typical afternoon westward flows of about 1 km s −1 were recorded over much of the interval, but important temporal and spatial variations were also seen as a result of the good time and space resolution of the experiment (5 min and 75 km, respectively). In particular, the westward flow was interrupted for about 10 min by a surge of poleward flow, possibly related to dynamic coupling occurring at the dayside magnetopause, such as a flux transfer event.