ENERGETIC PARTICLE PERSPECTIVE OF THE MAGNETOPAUSE

A detailed analysis is presented of energetic ( greater than 24 keV) particle data obtained from the Isee satellites during a series of magnetopause crossings which occurred at 0000 - 0400 hours UT ( similar 1030 hours LT) on November 20, 1977. The primary energetic particle data used are the three-dimensional distributions obtained from the Isee A satellite. Correlative magnetic field measurements are used to relate the particle behavior to magnetic field characteristics at and earthward of the magnetopause. The present results, having the added benefit of three-dimensional observations of the particle distribution, both confirm earlier results in some cases (e. g. , boundary motions and distortions) and present alternative and somewhat simpler explanations in other cases (e. g. , magnetosheath flow, intensity gradients at the boundary, effect of boundary microturbulence on particles).