Time: 2010-09-16 19:00:00
Speaker: Xi Zhang, Chenglong Zhang [IFTS]
Place: Rm. 413, Bld. 11#, Yuquan Campus
Abstract:
Speaker: Xi Zhang
Title: Shock associated with tearing mode in the presence of sub-Alfvénic shear flow
Abstract: This talk mainly presents the results of sub-Alfvénic shear flow influences on the tearing mode instability in the framework of compressible resistive MHD and compressible Hall MHD, including the reconnection rate under different shear flow conditions and the formation of MHD shocks out of the reconnection layer. It also introduces the basic concept of magnetic reconnection and MHD discontinuities.
Speaker: Chenglong Zhang
Title: Hall effect on nonlinear evolution of double tearing mode
Abstract: Hall effects play an important role in single tearing mode for a spatial scale with ion-inertia length. Therefore, it is believed that Hall effect will also alter the dynamic processes of double-tearing mode.
Hall effect on nonlinear evolution of double tearing mode In the Hall dominant system, the magnetic field configuration in the reconnection region evolves from a Y-type to an X-type geometry, which leads to fast reconnection in the late nonlinear growth phase. The maximum reconnection rate in the explosive growth phase is found to have a di2/5 η1/10 scaling and the maximum kinetic energy scales as di4/5..
In the weak Hall effect cases, it is found that the elongated thin current sheet formed in the early stage is broken into two X-points to form a magnetic island, instead of shrinking to an X-type structure in the late stage.
