Magnetic reconnection within MHD-scale Kelvin-Helmholtz
vortices triggered by electron inertial effects

T.K.M. Nakamura, and M. Fujimoto

In understanding the structure of an MHD-scale Kelvin-Helmholtz (KH) vortex,
magnetic reconnection within the vortex must not be neglected. Here we have
performed two-dimensional two-fluid simulations including finite electron
inertial effects to investigate this issue. An MHD-scale velocity shear is
set up and evolution of MHD-scale KH mode is followed. In this study, we 
focus on one basic case in which density is uniform and only in-plane 
magnetic field is present. The magnetic field is anti-parallel across the 
shear layer. In this case, magnetic reconnection occurs wihtin the flow of 
the KH vortex even if the Alfven Mach number of the shear is low. 
Furthermore, because reconnection
occurs between the two field lines on the opposite side of the shear layer,
there is the plasma mixing across the shear layer. These results imply that
magnetic reconnection in the flow of the MHD-scale dynamics is crucial.