MAGNETIC RECONNECTION INDUCED BY KELVIN-HELMHOLTZ INSTABILITY

MHD simulation study is performed to investigate magnetic reconnection induced by the Kelvin Helmholtz instability in the initially sheared magnetic field geometry as well as in the uniform magnetic field geome try. Slow mode rarefaction structures seen in the uniform field case a re not observed in the sheared field case. Dynamo action is less promi nent and the conversion of plasma flow energy into the other forms of energy is also smaller in the sheared field case than in the uniform f ield case. Momentum transport is mostly due to the hydrodynamic stress in the sheared field case, while the electromagnetic stress is domina nt in the uniform field case. The long term evolutions are also marked ly different in the two cases. In the uniform field geometry, the magn etic field lines twisted due to the Kelvin Helmholtz instability becom e reconnected and flattened so that they resume the straight held line structure which resembles the initial field geometry. The magnetic fi eld, however, is not uniform with smaller intensity in the central reg ion where the pressure balance is partially maintained by the enhanced thermal pressure. In the initially sheared magnetic field geometry, m agnetic reconnection continues to operate until the end of the simulat ion and the conversion of the flow energy into the thermal energy is s till seen.