Magnetotail Plasma Signatures of Pseudobreakups and Substorms

Using Polar/UVI global images, we have identified a period of successive minor auroral activations during which WIND was making a perigee pass through the near-Earth magnetotail. On the basis of images, these auroral brightenings are interpreted to be pseudobreakups due to the lack of significant global expansion. Large magnetic by the WIND spacecraft show a nearly one-to-one correspondence auroral intensifications. During intervals of large field auroral brightenings, energized ions have an Earthward velocity energized electrons generally remain isotropic. Closer inspection ion distribution functions indicate that the high velocity moments are not due to convective flows. Rather, the plasma is composed of a component and a stagnate cold component. We also trace the observed by WIND backwards in time to determine the source regions for the particles. Based upon these observations, we find that to zeroth order there is no difference in the behavior of the plasma during as compared to substorm expansive phase events.