Comparisons between EUV/IMAGE observations and numerical simulations of the plasmapause formation

Abstract. Simulations of plasmapause formation described in Pierrard and Lemaire (2004) predict the shape and equatorial distance of the plasmapause as a function of the geomagnetic activity index K_p. The equatorial positions predicted by this model are compared with the observations of EUV/IMAGE during the geomagnetic storm of 24 May 2000, substorm events of 10 June 2001 and 25 June 2000, and also during a prolonged quiet period (2 May 2001) when the plasmasphere was very extended. The formation of structures, like plumes and shoulders observed during periods of high geomagnetic activity, is quite well reproduced by the simulations. These structures are directly related to specific time sequences of K_p variations. The radial distances of the plasmapause are also reproduced, on average, by the model.

Keywords. Magnetospheric physics (Plasmasphere; Storms and substorms; Solar wind magnetosphere interactions)