HR: 0800h
AN: SM21A-0309    [Abstracts]
TI: Polarization properties of the fundamental mode and higher harmonics of standing shear Alfven waves in non-axisymmetric background magnetic fields.
AU: * Kabin, K
EM: kabin@phys.ualberta.ca
AF: The University of Alberta, 11322 89 avenue, University of Alberta, Department of Physics, Edmonton, AB T6G2G7, Canada
AU: Rankin, R
EM: rankin@phys.ualberta.ca
AF: The University of Alberta, 11322 89 avenue, University of Alberta, Department of Physics, Edmonton, AB T6G2G7, Canada
AU: Mann, I
EM: imann@phys.ualberta.ca
AF: The University of Alberta, 11322 89 avenue, University of Alberta, Department of Physics, Edmonton, AB T6G2G7, Canada
AU: Degeling, A W
EM: degeling@phys.ualberta.ca
AF: The University of Alberta, 11322 89 avenue, University of Alberta, Department of Physics, Edmonton, AB T6G2G7, Canada
AB: We present results concerning periods and polarizations of cold plasma ultra-low frequency (ULF) guided Alfven waves in a non-axisymmetric geomagnetic field model. The two fundamental modes which are differed by their polarizations, as well as their harmonics are included in the analysis. The background geomagnetic field is approximated by a compressed dipole model for which we propose a simple description in terms of Euler potentials. This study is motivated by the problem of outer-radiation belt electron energization by ULF waves, for which the polarization of the wave is of paramount importance. We consider an approximation in which Alfvenic waves are decoupled from compressional modes and find that the polarization of both the fundamental modelsas well as that of their harmonics can change significantly with local time. As a consequence, we find that the ULF wave's contribution to the MeV electron energization process can be localized in space. Furthermore, different harmonics of the fundamental mode also contribute to the electron energization in different regions of space.
DE: 2720 Energetic particles: trapped
DE: 2730 Magnetosphere: inner
DE: 2772 Plasma waves and instabilities (2471)
DE: 2774 Radiation belts
SC: SPA-Magnetospheric Physics [SM]
MN: 2007 Fall Meeting