HR: 0800h
AN: SH31B-05    [Abstracts]
TI: On the Formation of Ion-Acoustic Waves, Solitons, and Double Layers in the Vicinity of the Electrostatic Shocks
AU: * Lyu, L
EM: lyu@jupiter.ss.ncu.edu.tw
AF: National Central University, Institute of Space Science, National Central University, Chung-Li, 320-01, Taiwan
AU: Tsai, T
EM: tctsai@jupiter.ss.ncu.edu.tw
AF: National Central University, Institute of Space Science, National Central University, Chung-Li, 320-01, Taiwan
AB: Mixing of hot and cold electrons along the magnetic field line in the electron foreshock region can result in electron-electron two-stream instability and generate electron-acoustic waves. But recent observations showed that some of the upstream waves are ion acoustic waves. In this study, we use the ion-acoustic shock as an example to study the formation of nonlinear electrostatic waves and field-aligned potential jumps in the space plasma. Our Vlasov simulation results indicated that when the upstream ion beam energy is greater than the potential energy established by the hot downstream electrons, the shock ramp is characterized by an ion-acoustic soliton-like overshoot potential structure at the shock ramp. When the upstream ion beam energy is less than the potential energy established by the hot downstream electrons, the shock ramp is characterized by a monotonic-increase potential jump with an extended potential foot structure upstream from the shock ramp. The foot structure can accelerate the upstream cold electrons over a wide region and provide an excellent environment for the growth of ion acoustic waves from the ion-electron two-stream instability in this region. Long-term evolution of these ion acoustic waves into ion acoustic solitons and ion-acoustic double layers will also be discussed.
DE: 7829 Kinetic waves and instabilities
DE: 7839 Nonlinear phenomena (4400, 6944)
DE: 7851 Shock waves (4455)
DE: 7852 Solitons and solitary waves (4455)
DE: 7867 Wave/particle interactions (2483, 6984)
SC: SPA: Solar and Heliospheric Physics [SH]
MN: 2009 Joint Assembly