HR: 0800h
AN: IN21B-0480    [Abstracts]
TI: Simulation of mode conversion process from Upper-Hybrid wave to LO-mode wave in plasmasphere
AU: * Kalaee, M J
EM: j_kalaee2000@yahoo.com
AF: Department of Geophysics, Graduate School of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai, 980-8578, Japan
AU: Ono, T
EM: ono@stpp1.geophys.tohoku.ac.jp
AF: Department of Geophysics, Graduate School of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai, 980-8578, Japan
AU: Iizima, M
EM: iizima@stpp1.geophys.tohoku.ac.jp
AF: Department of Geophysics, Graduate School of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai, 980-8578, Japan
AU: Katoh, Y
EM: yuto@pparc.geophys.tohoku.ac.jp
AF: Department of Geophysics, Graduate School of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai, 980-8578, Japan
AU: Kumamoto, A
EM: kumamoto@stpp1.geophys.tohoku.ac.jp
AF: Department of Geophysics, Graduate School of Science, Tohoku University, 6-3 Aoba, Aramaki, Aoba-ku, Sendai, 980-8578, Japan
AB: The mode conversion occurs where one propagating mode is linearly coupled to other propagation mode. There are various phenomena related to the mode conversion process such as terrestrial continuum radiation, Auroral kilometric radiation, and Jovian decametric emissions. However, we often find observational results related to the mode conversion process in the region where theoretical assumptions are not valid; e.g., where WKB approximation might violated. To discuss these phenomena, we should evaluate the conversion process quantitatively by numerical experiments. For this purpose, we use Electron Hybrid code which is originally developed by Katoh (2003). In this scheme hot electrons are treated as particles while cold electrons are treated as a fluid. In order to establish a realistic model, we use Akebono satellite observation of plasmasphere. We assume two-dimensional simulation system where the uniform magnetic field B₀ is assumed to be in x-y plane. The wave vector was introduced to be aligned the x-axis direction making an oblique propagating to the external magnetic field. The plasma density gradient was set perpendicular to external magnetic field B₀ within the present study. Several simulations with different wave normal angle have been performed, with the same conditions such as, plasma frequency, steepness of density gradient and angular frequency in order to looking for the most efficient wave normal angle for mode conversion. The size of the simulation box used in the present study was determined depend on the wave normal angle. Based on the simulation results, we discussed how the wave coupling occurs in magnetized cold plasma by performing FFT analyses on wave electric field to examine spatial distribution of frequency/wave number spectra and by considering the polarization of wave modes propagating in the simulation system. Thus, the simulation results showed the generation of electromagnetic LO-mode wave through the mode conversion process from Upper Hybrid wave into LO-mode wave quantitatively. We also evaluated the efficiency of mode conversion depending on the wave normal angle.
DE: 0644 Numerical methods
DE: 0654 Plasmas
DE: 0689 Wave propagation (2487, 3285, 4275, 4455, 6934)
SC: Earth and Space Science Informatics [IN]
MN: 2007 Fall Meeting