HR: 1340h
AN: SM13B-1214    [Abstracts]
TI: Turbulent Mixing and Transport of the Solar Wind Plasma : Full Particle Simulation Study of the Kelvin-Helmholtz Instability
AU: * Matsumoto, Y
EM: ymatumot@stelab.nagoya-u.ac.jp
AF: Graduate School of Environmental Studies, Nagoya University, Integrated Studies division, Solar-Terrestrial Laboratory, Honohara 3-13, Toyokawa, 442-8507 Japan
AU: Hoshino, M
EM: hoshino@eps.s.u-tokyo.ac.jp
AF: Department of Earth and Planetary Science, University of Tokyo, Hongo 7-3-1, Bunkyo-ku, Tokyo, 113-0033 Japan
AB: Recent in-situ observations often show the mixing of the solar wind and magnetospheric plasmas in the low latitude boundary layer (LLBL), in which the Kelvin-Helmholtz instability is considered to be unstable. Those suggest that LLBL is a candidate for a source of plasmas and the Kelvin-Helmholtz instability plays an crucial role in a new transport mechanism. Even though numerous theoretical and computational studies have challenged to explain it so far, no one succeeded in transport of plasmas over a K-H vortex size and diffusive process that explains the observations. Hence, the transport mechanism of the solar wind plasma into the Earth magnetosphere in the situation of northward IMF has been a hot topic in magnetospheric physics. To elucidate the mixing and transport mechanism of the solar wind plasma we carried out two dimensional full particle simulation of the K-H instability. As a result, the strong density stratification triggered the strong turbulence which was also found in the two-dimensional MHD simulation (Matsumoto and Hoshino, GRL, 2004). The secondary Rayleigh-Taylor instability was found out to be unstable inside the stratified vortex structure and transport the dense solar wind plasma deep inside the magnetosphere. The resultant mixing area of the two plasmas increased anomalously fast as compared with the uniform density case. Hence the density stratification is an important factor for the effective mass transport across the velocity shear layer. The density stratification also introduced the ion kinetic effect in the non-linear stage. In a negative shear layer (the dawn side of the magnetopause) the finite Larmor radius (FLR) effect of the ion stabilized the onset of the secondary R-T instability and thus weakened the mass transport. In this presentation, the dawn-dusk asymmetry in the transport mechanism will be presented in detail as well as the onset mechanism of the turbulent mixing and transport by the K-H instability.
DE: 7863 Turbulence
DE: 2724 Magnetopause, cusp, and boundary layers
DE: 2752 MHD waves and instabilities
DE: 2753 Numerical modeling
DE: 2784 Solar wind/magnetosphere interactions
SC: SPA-Magnetospheric Physics [SM]
MN: 2004 AGU Fall Meeting