HR: 0800h
AN: SM41B-1185    [Abstracts]
TI: On the Formation of Field-Aligned Nonlinear Electrostatic Waves in Space Plasma
AU: * Tsai, T
EM: tctsai@jupiter.ss.ncu.edu.tw
AF: Institute of Space Science, National Central University, Chung-li, 320-01 Taiwan
AU: Lyu, L
EM: lyu@jupiter.ss.ncu.edu.tw
AF: Institute of Space Science, National Central University, Chung-li, 320-01 Taiwan
AB: Field-aligned nonlinear electrostatic waves have been observed in the magnetosheath, low-latitude boundary layer, plasmasheet, and upstream from the interplanetary shocks. Nonlinear electrostatic solitary waves with wave normal nearly perpendicular to the magnetic field have also been observed in the downward field-aligned current region, which are commonly named "electrostatic shock." Simulation study of electrostatic shocks, which satisfy the electrostatic shock jump conditions but different from the "electrostatic shock" observed in the downward field-aligned current region are studied by means of a non-periodic electrostatic Vlasov simulation code. In our simulation, the cold upstream plasma is injected into the hot and dense downstream plasma in the shock rest frame. An electrostatic potential is established within a few electron plasma oscillation periods. The cross-shock electrostatic potential can accelerate upstream electrons, reflect upstream ions, and reduce the amount of leakage electrons from the downstream side. The mixing of multiple plasma populations can result in different types of nonlinear electrostatic waves on the upstream side, downstream side, and in the shock transition layer. A multi-fluid linear wave analysis is carried out to explain the formation of nonlinear waves in the downstream region. A kinetic linear wave analysis is carried out to explain the formation of nonlinear waves in the upstream region. Since the nonlinear wave structures obtained in our simulations are very similar to the field-aligned nonlinear electrostatic waves observed in the space plasma, we propose that the nonlinear interactions between different plasma populations in the boundary layers may be responsible for the formation of various types of field-aligned electrostatic waves and potential jumps in the space plasma.
DE: 2724 Magnetopause and boundary layers
DE: 7829 Kinetic waves and instabilities
DE: 7851 Shock waves (4455)
DE: 7852 Solitons and solitary waves (4455)
DE: 7867 Wave/particle interactions (2483, 6984)
SC: SPA-Magnetospheric Physics [SM]
MN: Fall Meeting 2005