Global MHD Simulation of Magnetic Reconnection at the Earth's Magnetopause 

K. Park (Nagoya Univ.) and T. Ogino

Dynamics of Earth's magnetosphere can be controlled by magnetic reconnection 
between the geomagnetic field and the interplanetary magnetic field (IMF). 
Dayside magnetic reconnection is often described by two different models: 
antiparallel merging which occurs preferentially where the magnetosheath 
magnetic field is antiparallel to the geomagnetic field and subsolar merging 
occurs in the stagnation region where the IMF firstly encounters geomagnetic 
field. We have studied magnetic reconnection and magnetospheric dynamics by 
using a full 3-D MHD simulation when dipoles tilt as well as IMF By and Bz 
components simultaneously exists. The objectives of our study are to clearly 
show which one is more dominantly occurring at the dayside magnetopause. We 
find that antiparallel reconnection is more remarkable at the dayside 
magnetopause during intervals with southward IMF, a finite IMF By component 
and finite dipole tilt.