HR: 0800h
AN: SM41C-1205    [Abstracts]
TI: A numerical study of Hall effect in ULF waves
AU: * Kim, E
EM: ehkim@khu.ac.kr
AF: Department of Astronomy and Space Science, Kyung Hee University, Yongin, Kyunggi, 449-701 Korea, Republic of
AU: Lee, D
EM: dhlee@khu.ac.kr
AF: Department of Astronomy and Space Science, Kyung Hee University, Yongin, Kyunggi, 449-701 Korea, Republic of
AU: Kim, K
EM: khan@kasi.re.kr
AF: Korea Astronomy and Space Science Institute, Youseong, Taejeon, 305-348 Korea, Republic of
AU: Lysak, R L
EM: bob@fields.space.umn.edu
AF: School of Physics and Astronomy, University of Minnesota, Church St. SE, Minneapolis, MN 55455 United States
AB: Hall magnetohydrodynamics (MHD) is defined to be conventional MHD with the Hall term in Faraday's law. When the characteristic scale length is small compared to the collisionless ion skin depth (c/ ω_pi) and the characteristic time scale is short compared to the inverse ion cyclotron frequency (t<ω_ci^-1), the single fluid MHD approximation is no longer valid. The Hall MHD formalism treats the plasma as a single fluid like MHD does, though it takes into account the finite ion inertia. In this way it is possible to describe waves with frequencies up to ω ≈ ω_ci. Since the electron mass is still negligible, its application is limited to frequencies well below the lower hybrid frequency (ω << ω_LH). Hall MHD has been studied in various wave modes such as the surface Alfven wave, the kinetic Alfven wave, and the nonlinear Alfven wave. Recently it becomes evident that Hall physics also plays a critical role in magnetic reconnection process. However, it is still of considerable interests to investigate how electrons and ions behave in inhomogeneous plasmas when the frequency ranges from very low values of MHD to ω_ci . In particular, no studies have been made on how electron and ion oscillations are differentiated for different wave modes. In this study, we present a numerical study of Hall effect in ULF waves by adopting the multi-fluid wave model, which has recently been developed by Kim and Lee [2003]. When the frequency ranges from MHD waves to ion cyclotron waves, electron/ion velocities, electric and magnetic fields, and current density are investigated for both shear Alfven mode and compressional mode, respectively. At Alfven resonances, it is found that the electron and the ion velocities of compressional component are significantly decoupled. At the compressional modes such as cavity modes, the electron and the ion velocities of shear modes are decoupled.
DE: 2483 Wave/particle interactions (7867)
DE: 2700 MAGNETOSPHERIC PHYSICS (6939)
DE: 2772 Plasma waves and instabilities (2471)
DE: 2784 Solar wind/magnetosphere interactions
SC: SPA-Magnetospheric Physics [SM]
MN: Fall Meeting 2005