HR: 10:50h
AN: SM31E-03    [PDF]
TI: Ion Dynamics of the Inner Tail and Reconnection Signatures
AU: * Krauss-Varban, D
EM: varban@ece.ucsd.edu
AF: ECE Department, UCSD, 9500 Gilman Drive, La Jolla, CA 92093-0407 United States
AU: Karimabadi, H
EM: homa@ece.ucsd.edu
AF: ECE Department, UCSD, 9500 Gilman Drive, La Jolla, CA 92093-0407 United States
AU: Quest, K B
EM: quest@ece.ucsd.edu
AF: ECE Department, UCSD, 9500 Gilman Drive, La Jolla, CA 92093-0407 United States
AB: During active times, the magnetotail current layer thins to below the thermal ion gyro radius, over a large distance from just past the transition to dipolar field lines to beyond 20R$_{E}$. These scales and the simultaneous presence of cold lobe ions, current-carrying hot central plasmasheet ions, as well as highly energized ions create an environment rich in ion-kinetic effects that often dominate the dynamics of the tail. While crucial, ion-kinetic physics is not contained in local or global fluid (MHD) descriptions. It is argued that the ions also play a larger role than previously assumed in communicating perturbations earthward. Our 3-D hybrid simulations (kinetic ions, electron fluid) have demonstrated that earthward transport of energetic, essentially unmagnetized ions is fast and efficient, and can be associated with a large heat flux that initially is located close to the neutral sheet. Both the energetic ions and parallel currents can arrive long before the dipolarization front on what corresponds to relatively low-latitude field lines. Understanding the characteristics of these ions has recently become of greater interest, considering improved methods of monitoring and imaging near-Earth and precipitating energetic ions. However, in previous studies we used a traditional equilibrium, which does not provide a good description of the inner tail. Using techniques that generate numerical equilibria, we have now improved our model by including the transition to the dipolar region. We discuss the stability of these equilibria and present results that show the passive and active impact of the near-Earth region on reconnection signatures.
DE: 2716 Energetic particles, precipitating
DE: 2736 Magnetosphere/ionosphere interactions
DE: 2744 Magnetotail
DE: 2748 Magnetotail boundary layers
DE: 2788 Storms and substorms
SC: SPA - Magnetospheric Physics [SM]
MN: 2003 Fall Meeting