HR: 17:23h
AN: SM24A-06    [Abstracts]
TI: Solar Wind Driven and Inertial Reconnection in the Jovian Magnetotail
AU: * Walker, R J
EM: rwalker@igpp.ucla.edu
AF: Institute of Geophysics and Planetary Physics and Department of Earth and Space Science, UCLA, Los Angeles, CA 90095-1567 United States
AU: Ogino, T
EM: ogino@stelab.nagoya-u.ac.jp
AF: Solar Terrestria Environment Laboratory, Nagoya University, Toyokawa, 442-8507 Japan
AU: Fukazawa, K
EM: fukazawa@stelab.nagoya-u.ac.jp
AF: Solar Terrestria Environment Laboratory, Nagoya University, Toyokawa, 442-8507 Japan
AB: Reconnection in the terrestrial magnetosphere is largely controlled by the interplanetary magnetic field (IMF). For a southward IMF magnetic flux removed from the dayside magnetopause to the tail lobes is returned to the dayside by magnetotail reconnection. In simulation studies for a steady southward IMF, a single X-line O-line pair forms in the magnetotail. With time the O-line moves tailward but the X-line stays in the near-Earth magnetotail. In an analogous simulation at Jupiter a northward IMF leads to dayside reconnection and the formation of an X-O pair in the magnetotail. However, in the rapidly rotating Jovian magnetosphere both neutral lines exit the tail and a second X-O pair form in the near-Jupiter tail. This process repeats with a period of 30 to 70 hours [Fukazawa et al., GRL submitted, 2004]. However, reconnection can occur in the Jovian magnetotail even in the absence of dayside reconnection. On the dayside rotating magnetic flux tubes filled with outflowing Iogenic plasma are constrained by the dayside magnetopause. However on the nightside they are no longer constrained and can stretch far into the tail. In the early morning quadrant these stretched closed flux tubes can reconnect. We have carried out a series of global magnetohydrodynamic simulations of the interaction of the Jovian magnetosphere with the solar wind to study the evolution of these inertially reconnecting flux tubes. In this study we have examined the changes in the Jovian magnetotail following a decrease in the solar wind dynamic pressure in the absence of an IMF. We find an X-O line pair form on closed field lines in the dawn quadrant as expected. The O-line moves tailward and toward the dawn magnetopause where it exits the system. Like tail reconnection at Earth, the X-line does not move. When we further reduced the dynamic pressure the location at which the X-O pair formed moved tailward. At Earth the field lines from the tail reconnection map to the polar edge of the auroral oval. At Jupiter the oval is thought to lie much closer to the planet. We have used calculations of the energy flux to the ionosphere as a proxy for auroral emissions and will present the auroral signatures of both driven and inertial reconnection.
DE: 7827 Kinetic and MHD theory
DE: 6220 Jupiter
DE: 2744 Magnetotail
DE: 2753 Numerical modeling
DE: 2756 Planetary magnetospheres (5443, 5737, 6030)
SC: SPA-Magnetospheric Physics [SM]
MN: 2004 AGU Fall Meeting