Auroral Data Analysis.

Data from the soft particle spectrometers on the ISIS-1 and -2 satellites were reduced, analyzed, and compared with other observations to reveal auroral and ionospheric effects. The satellite observations confirm Pikes suggestion that the regions of auroral particle precipitation are characterized by strong ionospheric F region irregularities, which can be observed and monitored by ionosondes or HF radars. The magnetospheric cleft or dayside auroral region moves to lower latitudes when the interplanetary magnetic field turns southward but also in direct and rapid response to nightside auroral substorm activity. The polar cap is generally subject to a uniform and weak polar rain or flux of magnetosheath plasma, as well as localized bursts or showers. During major geomagnetic storms there is a greatly enhanced precipitation of electrons with several keV energies, called a polar squall. The nightside expansion phase precipitation pattern is complex, but a characteristic pattern is correlated with substorm time or phase, the poleward motion being followed by a collapse or weakening of the electron flux behind it.