NUMERICAL-SIMULATION OF THE INDIVIDUAL-MODE EVOLUTION IN A SLAB JET

Two-dimensional magnetohydrodynamic (MHD) simulations are performed to study the evolution of the Kelvin-Helmholtz (KH) instability for a sl ab jet moving parallel to the uniform magnetic field. Surface modes ar e excited and the time evolution of the individual mode is observed. T he instability is very disruptive when the excited perturbations on th e two side boundaries are antisymmetric. The long term evolution of th e antisymmetric perturbation shows a kink-like magnetic field structur e after multiple reconnection events, while the symmetric perturbation yields wavy signatures only around the jet boundary. These MHD result s are markedly different from the hydrodynamic results, although the m agnetic field intensity in the present case is very small.