Correlation between quasiperiodic disturbances in the magnetosphere tail and surface Pi2 pulsations

The event in which Pi2s correlate with oscillations of the earthward plasma flow is under consideration. In our opinion, the plasma flow modulation is caused by the plasma layer waveguide mode exciting Alfven waves. Impulse Pi2 disturbances in the night magnetosphere are usually considered as a damping wave train at the moment of sub-storm commencement. However, several nearly simultaneous sources can contribute to the structure of Pi2 oscillations. Particularly, for some events Pi2s have been interpreted as a forced response to quasiperiodic variations of the earthward plasma flow in the magnetosphere tail (Bursty Bulk Flows) [1]. Here we examine one of such events from some other point of view.