HR: 12:05h
AN: SM22A-08    [Abstracts]
TI: Generation of Electrostatic Cyclotron Harmonic (ECH) Waves due to Loss Cone Distribution Functions
AU: * Umeda, T
EM: taka@igpp.ucla.edu
AF: Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095-1567 United States
AU: Ashour-Abdalla, M
EM: mabdalla@igpp.ucla.edu
AF: Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095-1567 United States
AU: Ashour-Abdalla, M
EM: mabdalla@igpp.ucla.edu
AF: Department of Physics and Astronomy, University of California, Los Angeles, Los Angeles, CA 90095-1547 United States
AU: Schriver, D
EM: dave@igpp.ucla.edu
AF: Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095-1567 United States
AU: Richard, R L
EM: rrichard@igpp.cualedu
AF: Institute of Geophysics and Planetary Physics, University of California, Los Angeles, Los Angeles, CA 90095-1567 United States
AU: Coroniti, F V
EM: coroniti@astro.ucla.edu
AF: Department of Physics and Astronomy, University of California, Los Angeles, Los Angeles, CA 90095-1547 United States
AU: Matsumoto, H
EM: matsumot@rish.kyoto-u.ac.jp
AF: Research Institute for Sustainable Humanosphere, Kyoto University, Gokasho, Uji, Kyoto, 611-0011 Japan
AB: Electron cyclotron harmonic (ECH) waves are observed in the Earth's magnetosphere in the nightside near-Earth equatorial region. Observations indicate that a loss cone feature in the electron distribution function generates ECH waves, which result in pitch angle diffusion and the formation of a highly anisotropic "pancake" type of distribution in the low energy electron population. Electrostatic and electromagnetic waves are driven by loss cone distributions in the presence of cold plasma, which is known to strongly affect the linear dispersion properties of ECH waves. To examine the detailed properties of the ECH waves and ensuing wave-particle interactions, two-dimensional (2.5D) electromagnetic Particle-In-Cell (PIC) and Vlasov simulations are employed. The heating of the cold electrons and their effects on the saturation of the ECH waves will be determined. Implications for diffuse auroral precipitation will be discussed.
DE: 7843 Numerical simulation studies
DE: 7867 Wave/particle interactions
DE: 7871 Waves and instabilities
DE: 2730 Magnetosphere--inner
DE: 2772 Plasma waves and instabilities
SC: SPA-Magnetospheric Physics [SM]
MN: 2004 AGU Fall Meeting