HR: 1340h
AN: SM53B-0404    [Abstracts]
TI: Instability at the leageing edge of a reconnection jet
AU: * Tandokoro, R
EM: rtdokoro@geo.titech.ac.jp
AF: Department Earth and Planetary Sciences, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo, 152-8551 Japan
AU: Fujimoto, M
EM: fujimoto@geo.titech.ac.jp
AF: Department Earth and Planetary Sciences, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo, 152-8551 Japan
AB: Magnetic reconnection is the one of the most important phenomena in space plasma physics, which is considered to concern large scale energetic phenomena. Especially, a high-speed plasma jet which occurs with energy release by magnetic reconnection, so called reconnection jet, is considered to play an important role in an energetic process such as plasma particle acceleration in solar flares. In spite of the importance of the reconnection jet, however, little attention has been paid to its dynamics. In this study, we focus on behavior of the reconnection jet and try revealing its property conducting three-dimensional MHD simulations. In our simulations, initial condition of the magnetic field we employed is the one-dimensional Harris current sheet model. Magnetic reconnection is initiated by the time-independent and spatial fixed anomalous resistivity. We add small perturbations, that their wave number vector is directed to initial current direction, to plasma pressure and density, and study how the reconnection jet develops. Under this condition, numerical results show that the leading portion of the reconnection jet is deformed into wavy configuration and grows to show mushroom-like shape on the central current sheet plane, that is, the perturbations are brought up into unstable state with development of the reconnection jet. In the reconnection process, the leading part of a reconnection jet pushes and compresses the standing plasma ahead of it, and a strong pressure and density gradient develops between the reconnection jet and the plasma in front of the jet. Consequently, in this circumstance, we might consider the unstable state at the leading edge of the reconnection jet as the interchange instability. A reconnection jet has more dynamic structure than we have thought. This implies the capability that the structure of the leading part of the reconnection jet influence plasma energetic processes. We discuss this possibility by exhibiting the extremely complicated flow pattern of the jet in the later stage of development of the reconnection jet. And we also mention the influence on the structure of the jet and ambient plasma and field in the more realistic and general situation in which the guide field exists.
DE: 2700 MAGNETOSPHERIC PHYSICS
DE: 2772 Plasma waves and instabilities
SC: SPA-Magnetospheric Physics [SM]
MN: 2004 AGU Fall Meeting