HR: 0800h
AN: SM31C-0571    [Abstracts]
TI: Slow-Mode Mach-Cone-Like Solitary Waves Found in the Simulation Study of Jet-Flow- Associated Kelvin-Helmholtz Instability in the MHD Plasmas
AU: Lai, S
EM: lucky@jupiter.ss.ncu.edu.tw
AF: National Central University, Institute of Space Science, Namtional Central University, Chung-Li, 320-01, Taiwan
AU: * Lyu, L
EM: lyu@jupiter.ss.ncu.edu.tw
AF: National Central University, Institute of Space Science, Namtional Central University, Chung-Li, 320-01, Taiwan
AB: Jet-flow-associated Kelvin-Helmholtz (K-H) instabilities are studied by means of a two-dimensional magnetohydrodynamic (MHD) simulation. In addition to the vortex structures and the undulant surface waves, we also obtain fast-mode and slow-mode Mach-cone-like solitary waves at the saturation stage of the jet-flow- associated K-H instabilities. The fast-mode Mach-cone-like solitary waves can be found when the fast-mode Mach numbers of the surface waves are greater than one. The slow-mode Mach-cone-like solitary waves are found for the first time in a limited range of M_SL0y, θ₀, and β₀, where M_SL0y is the slow-mode Mach number of the surface disturbances observed in the ambient plasma rest frame, θ₀ is the angle between the jet-flow direction and the direction of the ambient magnetic field, and β₀ is the plasma β of the ambient plasma. A theoretical model is proposed to explain the formation and the characteristics of the slow-mode Mach-cone-like solitary waves. The flaring angles of the slow-mode Mach-cone- like solitary waves measured from the simulation results are in good agreement with the flaring angles predicted by the theoretical model. Applications of our results to the observations in the space plasma are discussed.
DE: 2724 Magnetopause and boundary layers
DE: 2748 Magnetotail boundary layers
DE: 2752 MHD waves and instabilities (2149, 6050, 7836)
DE: 7839 Nonlinear phenomena (4400, 6944)
DE: 7852 Solitons and solitary waves (4455)
SC: SPA-Magnetospheric Physics [SM]
MN: 2007 Fall Meeting