HR: 1340h
AN: SM13A-0329    [Abstracts]
TI: A Study of IMF's Penetration of the Earth's Magetotail via 3-D Global MHD Simulations and Virtual Reality System
AU: Matsuoka, D
EM: daisuke@velvet.cs.ehime-u.ac.jp
AF: Ehime University, 3 Bunkyo-cho, Matsuyama, 790-8577 Japan
AU: * Murata, K T
EM: murata@cite.ehime-u.ac.jp
AF: Ehime University, 3 Bunkyo-cho, Matsuyama, 790-8577 Japan
AU: Fujita, S
EM: sfujita@mc-jma.ac.jp
AF: Meteorological College, 7-4-81 Asahi-machi, Kashiwa, 277-0852 Japan
AU: Tanaka, T
EM: tatanaka@geo.kyushu-u.ac.jp
AF: Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka, 812-8581 Japan
AU: Matsumoto, H
EM: matsumoto@rish.kyoto-u.ac.jp
AF: Kyoto University, Gokasho, Uji, 611-0011 Japan
AU: Omura, Y
EM: omura@rish.kyoto-u.ac.jp
AF: Kyoto University, Gokasho, Uji, 611-0011 Japan
AB: It is well known that the By component observed in the Earth's magnetotail, both in the tail lobe and in the plasma sheet, often show good correspondence with the By of the IMF observed in the upstream region of the Earth. It is believed that the IMF 'sinks into' or 'penetrates' the Earth's magnetosphere. However, the process how the IMF sinks into the mageototail is still unclear. We performed 3-D global MHD simulations to study the mechanism for the IMF to penetrate the Earth's magnetotail. We first performed several global MHD simulations using simple IMF models as input parameters, with no By component in the IMF. In both cases with Bz > 0 and Bz < 0, no penetration of the IMF By component was found in the magnetotail. Next, we performed simulations with By ≠ 0. In both cases with Bz > 0 and Bz <, Bz components in the magnetotail (both in the lobe region and in the plasma sheet) were found. What was more interesting is the time-dependent changes of the By components observed in the magnetotail. We found that By components in the plasma sheet are well synchronized with the change of those in the IMF. Using a virtual reality system, we carefully examined how the configurations of magnetic filed lines of the IMF develop in time. We found in the 3-D virtual space that there are two-step reconnections for the IMF to penetrate the magnetotail. At the first reconnection, which takes place at the nose of the magnetosphere, the IMF magnetic field lines are reconnected with the Earth magnetic fields. The 'open' field lines, which are generated by the first reconnections, are draped in the anti-sunward direction, to encounter the close magnetic field lines at the tail flank region. There occurs the second reconnection both at the dawn side and dusk side of the magnetotail. Since the two open magnetic field lines are again reconnected at the magnetotail flank, finally the magnetic field lines, the both side of which are connected with the IMF, show up. In order to examine the story above, we used real observation data at the upstream region of the Earth as input parameters for the 3-D MHD simulations. The simulatio n results will be directly compared with spacecraft observations in the magnetotail region.
UR: http://www.infonet.cite.ehime-u.ac.jp/VEMS
DE: 7800 SPACE PLASMA PHYSICS
DE: 7833 Mathematical and numerical techniques (0500, 3200)
DE: 7835 Magnetic reconnection (2723, 7526)
DE: 7959 Models
DE: 7974 Solar effects
SC: SPA-Magnetospheric Physics [SM]
MN: Fall Meeting 2005