HR: 1340h
AN: SH44A-1713    [Abstracts]
TI: Magnetic reconnection with multiple X-lines in an open system: Two fluid simulations with finite electron inertial effects
AU: * Sekiya, H
EM: sekiya.h.aa@m.titech.ac.jp
AF: Department of Earth and Planetary Sciences, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo, 152-8550, Japan
AU: Nakamura, T
EM: takuma@stp.isas.jaxa.jp
AF: Institute of Space and Astronautical Science, 3-1-1 Yoshinodai, Sagamihara, 229-8510, Japan
AU: Fujimoto, M
EM: fujimoto@stp.isas.jaxa.jp
AF: Institute of Space and Astronautical Science, 3-1-1 Yoshinodai, Sagamihara, 229-8510, Japan
AB: To understand large-scale development of magnetic reconnection, it is necessary to consider reconnection triggered at multiple X-points in a long current sheet and associated coalescence of magnetic islands. While a number of numerical simulations have been performed to study multiple X-point magnetic reconnection, most of these simulations are done in periodic systems, in which the large-scale development of magnetic reconnection tends to be disturbed at the boundary. Thus, in this study, we perform two-fluid simulations of multiple X-point magnetic reconnection using an open boundary condition. Here the X-points, which are located with a spatial interval of 12.8D, are initially imposed by adding magnetic perturbations. First, when the initial perturbations having the same amplitude are added at three X-points, the two X-lines at the ends preferentially survive and the middle X-line is vanished by a pair of converging flows from the both ends. Then the two X-lines at the ends retreat from each other. Next, when we enhance the amplitude of initial perturbation at one of the ends by a factor of 1.2 or more, only the enhanced X-line can survive and two other X-lines disappeared. When the X-line at one of the ends is enhanced by a factor of 1.1, however, X-lines at both ends survive and retreat from each other. We have confirmed that such coexistence of both X-lines at the ends takes place at larger amplitude difference as the distance between the end-X-lines are increased. Furthermore, we have also confirmed that when the amplitude of the initial perturbation at the middle X-point is enhanced, the coexistence of two end X-lines occur more easily. These results suggest that more than one X-line can coexist even in the final stage of the development of magnetic reconnection driven in a long current sheet. In addition, we have found more varieties to be introduced to the final stage when the open boundary on one of the sides is changed to a closed boundary. In our presentation, these new simulation results will be shown.
DE: 2723 Magnetic reconnection (7526, 7835)
DE: 2744 Magnetotail
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2007 Fall Meeting