HR: 14:40h
AN: SM43D-05 INVITED     [Abstracts]
TI: Auroral Particle Acceleration and Formation of Double Layer From Nonlinear MHD Wave Packet Interaction
AU: * Song, Y
EM: yan@fields.space.umn.edu
AF: University of Minnesota, 116 Church Street SE, Minneapolis, MN 55455 United States
AU: Lysak, R L
EM: bob@aurora.space.umn.edu
AF: University of Minnesota, 116 Church Street SE, Minneapolis, MN 55455 United States
AB: Most models and theories of double layer are based on the assumed existence of a parallel potential drop, without explaining how the parallel potential drops are formed. Based on the recently-developed dynamical theory of the generation of parallel electric fields, a dynamical double layer model will be given, where the parallel potential drop is maintained by a localized dynamo. The formation of double layers is often the result of nonlinear interaction of MHD wave packets rather than sinusoidal waves. During the nonlinear interaction, a combination of an enhanced localized magnetic stress (inductance) and a parallel potential drop (parallel capacitor) will be formed due to the approximate conservation of magnetic helicity. Energy to support a significant double layer and the energization of charged particles comes from releasing the local free magnetic energy and/or kinetic energy associated with the azimuthal magnetic and velocity shears during the nonlinear wave packet interaction. The theoretical prediction of the relationship between (i) the double layer formation and (ii) plasma density, signature of magnetic and electric field and velocity field will be presented.
DE: 2704 Auroral phenomena (2407)
DE: 2712 Electric fields (2411)
DE: 2721 Field-aligned currents and current systems (2409)
DE: 2736 Magnetosphere/ionosphere interactions (2431)
DE: 2752 MHD waves and instabilities (2149, 6050, 7836)
SC: SPA-Magnetospheric Physics [SM]
MN: Fall Meeting 2005