Quantitative Comparison of Measured Plasma Sheet Electron Energy Flux and Remotely Sensed Auroral Electron Energy Flux

M. O. Fillingim1, G. K. Parks1, 2, D. Chua1, G. A. Germany3, R. P. Lin2, and M. McCarthy1

1Department of Earth and Space Sciences, University of Washington, Seattle
2Space Sciences Laboratory, University of California, Berkeley
3Center for Space Plasma, Aeronomy, and Astrophysics Reseach, University of Alabama in Huntsville, Huntsville

Presented at the 2001 AGU Fall Meeting, San Francisco, CA, December 10 - 14, 2001


Abstract

In situ plasma sheet observations and auroral images give us two views of magnetospheric dynamics. With in situ observations, we get a detailed point measurement; auroral images give us a global view. Previous studies have shown an excellent correlation between dynamic plasma behavior in the plasma sheet and auroral activity. Here we extend the previous work with quantitative comparisons between the two regions. We directly compare the electron energy flux measured in the plasma sheet with the electron energy flux into the ionosphere inferred from auroral images. We find that during quiet times, the plasma sheet is able to supply the aurora with nearly all of the observed energy flux. During intervals of intense auroral emission, the electron spectrum in the conjugate region of the plasma sheet changes, increasing the amount of energy flux incident on the ionosphere. However, the increases in the plasma sheet energy flux is not enough to account for the inferred energy flux into the ionosphere from the images by nearly an order of magnitude. This implies that additional energy flux must be entering the loss cone through pitch angle diffusion or through the presence of parallel electric fields between the plasma sheet and the ionosphere during intervals of intense auroral emission. A likely source of this additional energy flux is the low altitude auroral acceleration region.



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Contact Information:
Matt Fillingim Matt Fillingim
matt at ess dot washington dot edu matt at ssl dot berkeley dot edu
University of Washington University of California, Berkeley
Department of Earth and Space Sciences Space Sciences Laboratory # 7450
Box 351310 7 Gauss Way
Seattle, WA 98195-1310 Berkeley, CA 94720-7450