Two-dimensional ionospheric convection signatures for a Pc5 event observed by SuperDARN radars

*Tetsuo Motoba[1] ,Takashi Kikuchi [2]
Univ. of Electro-Communications[1]
Communications Research Laboratory[2]

In this paper, we present data from SuperDARN radars describing the two-dimensional ionospheric convection signatures responsible for a Pc5 event on November 8, 2000, attributed to a large enhancement in the solar wind dynamic pressure. During this interval, the SuperDARN radars (Iceland East and Finland radars) in the morning sector measured periodic intensifications in the line-of-sight (LOS) plasma velocity, corresponding to ground magnetic variations within the field-of-view of the radars. The LOS velocity vectors merged by a pair of radars indicate the presence of some convection vortices with alternating rotation directions. The vortices are centered at about 75° magnetic latitude and 8-10 MLT. The spatial and temporal evolution of the convection patterns obtained by radars seems to be in reasonable agreement with that of the equivalent convection patterns deduced from horizontal magnetic variations. The SuperDARN radar observations provide strong evidence that vortical ionospheric convection sinatures play a major role in Pc5 magnetic fluctuations on the ground.