HR: 0800h
AN: SM51A-0265    [Abstracts]
TI: What is the Alfvenic Dissipation Scale in the Auroral Region?
AU: * Lund, E J
EM: Eric.Lund@unh.edu
AF: University of New Hampshire, Space Science Center, Morse Hall, 39 College Rd., Durham, NH 03824, United States
AB: The auroral acceleration region includes a large amount of turbulence which contributes to acceleration of electrons along the magnetic field and ions perpendicular to the magnetic field. Much of this turbulence is believed to be Alfvénic in nature. However, no theory of turbulence specifically applicable to the auroral acceleration region has been developed, and the present observational understanding of the turbulence seems to be inconsistent with theories of Alfvénic turbulence that have been developed for the interplanetary medium. In particular, the standard theory of Alfvénic turbulence predicts that in the auroral acceleration region the waves should be heavily damped at scales which are long compared with the ion gyroradius, while many models of ion heating require significant wave power at scales comparable to or less than the ion gyroradius in order to heat ions stochastically in the perpendicular direction. We discuss some possible explanations for the apparent discrepancy between standard Alfvénic turbulence theory and the auroral region, and we present a preliminary investigation into the dissipation scale as observed with the FAST satellite.
DE: 2149 MHD waves and turbulence (2752, 6050, 7836)
DE: 2704 Auroral phenomena (2407)
DE: 2772 Plasma waves and instabilities (2471)
DE: 7836 MHD waves and instabilities (2149, 2752, 6050)
DE: 7863 Turbulence (4490)
SC: SPA-Magnetospheric Physics [SM]
MN: 2007 Fall Meeting