HR: 1340h
AN: SM33A-0433 [Abstracts]
TI: Possibility of an Alfvenic Wave Resonator in the Magnetosphere*
AU: * Mithaiwala, M
EM: mithaiwa@yahoo.com
AF: NRC-NRL Postdoc, US Naval Research Lab
4555 Overlook Ave., SW, Washington, DC 20375
United States
AU: Ganguli, G
EM: gang@ppdmail.nrl.navy.mil
AF: Naval Research Lab, US Naval Research Lab
4555 Overlook Ave., SW, Washington, DC 20375
United States
AU: Rudakov, L
EM: leonid.roudakov@nrl.navy.mil
AF: Naval Research Lab, US Naval Research Lab
4555 Overlook Ave., SW, Washington, DC 20375
United States
AU: Rudakov, L
EM: leonid.roudakov@nrl.navy.mil
AF: Icarus Research Inc., P.O. Box 30780, Bethesda, MD 20824
United States
AB:
There has been recent activity in understanding the origin of high energy (>1 MeV) 'killer
electrons' in the Earth's magnetosphere. Previous work has identified the energization
mechanism to be quasilinear diffusion involving whistler and ion-cyclotron waves , which are generated by temperature
anisotropy. It is known that whistler waves, through reflection at the lower-hybrid resonance, can form a resonator. We find
that in a multi-ion species environment, such as the Earth's magnetosphere, the bi-ion rotation (cutoff)
frequency and Buchsbaum (resonance) frequency are important for the propagation and evolution of Alfvenic waves near the
ion-cyclotron frequency. Here we show that Alfvenic waves with (k∥ >> kz) can be captured by a magnetic cavity to
form a strongly localized Magnetospheric Resonator which can interact with the electrons over a long time period and can lead
to both energization and loss of the electrons. The Alfvenic waves can be generated by a ring distribution of one of the ion
species. Ring ion distributions are known to form when the solar wind interacts with the magnetosphere or a comet interacts
with the solar wind, and by the release of chemicals in the magnetosphere.
* Work supported by ONR
1 Mithaiwala, M.J. and W. Horton. JGR 110. July 2005.
2 Ganguli, G. and L. Rudakov. Phys. Plasmas 12. April 2005.
DE: 2720 Energetic particles: trapped
DE: 2772 Plasma waves and instabilities (2471)
DE: 2788 Magnetic storms and substorms (7954)
DE: 7829 Kinetic waves and instabilities
DE: 7867 Wave/particle interactions (2483, 6984)
SC: SPA-Magnetospheric Physics [SM]
MN: Fall Meeting 2005