A three-dimensional(3-D)global hybrid simulation is carried out for the generation and structure of magnetic reconnection in the magnetosheath due to interaction of an interplanetary Tangential Discontinuity(TD)with t...A three-dimensional(3-D)global hybrid simulation is carried out for the generation and structure of magnetic reconnection in the magnetosheath due to interaction of an interplanetary Tangential Discontinuity(TD)with the bow shock and magnetosphere.Runs are performed for solar wind TDs possessing diFFerent initial half-widths.As the TD propagates through the bow shock toward the magnetopause,it is greatly narrowed by a two-step compression processes,a "shock compression" followed by a subsequent "convective compression".In cases with a relatively thin solar wind TD,3-D patchy reconnection is initiated in the transmitted TD,forming magnetosheath flux ropes.Multiple components of ion particles are present in the velocity distribution in the magnetosheath merging,accompanied by ion heating.For cases with a relatively wide initial TD,a dominant single X-line appears in the subsolar magnetosheath after the transmitted TD is narrowed.A shock analysis is performed for the detailed structure of magnetic reconnection in the magnetosheath.Rotational Discontinuity(RD)/TimeDependent Intermediate Shock(TDIS)are found to dominate the reconnection layer,which and some weak slow shocks are responsible for the ion heating and acceleration.展开更多
The effects of electron pressure gradient term in the generalized Ohm’ law is studied by 3 D MHD simulation code under condition of high plasma Beta and small ion inertial length. The results show that the electron p...The effects of electron pressure gradient term in the generalized Ohm’ law is studied by 3 D MHD simulation code under condition of high plasma Beta and small ion inertial length. The results show that the electron pressure gradient term increases the velocity of electrons and ions, and therefore increases the field aligned current, finally leading to the increase of core magnetic field. Since the field aligned current is the principal way by which the magnetosphere is coupled with the ionosphere, the electron pressure gradient term enhances the coupling of magnetosphere ionosphere. The electron pressure gradient can also generate the dynamic Alfven wave. It is supposed that this Alfven wave may change the velocity of particles.展开更多
基金Supported by NSF grant ATM-0646442 to Auburn University and the National Natural Science Foundation of China(NSFC) grant 40640420563 to Wuhan University
文摘A three-dimensional(3-D)global hybrid simulation is carried out for the generation and structure of magnetic reconnection in the magnetosheath due to interaction of an interplanetary Tangential Discontinuity(TD)with the bow shock and magnetosphere.Runs are performed for solar wind TDs possessing diFFerent initial half-widths.As the TD propagates through the bow shock toward the magnetopause,it is greatly narrowed by a two-step compression processes,a "shock compression" followed by a subsequent "convective compression".In cases with a relatively thin solar wind TD,3-D patchy reconnection is initiated in the transmitted TD,forming magnetosheath flux ropes.Multiple components of ion particles are present in the velocity distribution in the magnetosheath merging,accompanied by ion heating.For cases with a relatively wide initial TD,a dominant single X-line appears in the subsolar magnetosheath after the transmitted TD is narrowed.A shock analysis is performed for the detailed structure of magnetic reconnection in the magnetosheath.Rotational Discontinuity(RD)/TimeDependent Intermediate Shock(TDIS)are found to dominate the reconnection layer,which and some weak slow shocks are responsible for the ion heating and acceleration.
文摘The effects of electron pressure gradient term in the generalized Ohm’ law is studied by 3 D MHD simulation code under condition of high plasma Beta and small ion inertial length. The results show that the electron pressure gradient term increases the velocity of electrons and ions, and therefore increases the field aligned current, finally leading to the increase of core magnetic field. Since the field aligned current is the principal way by which the magnetosphere is coupled with the ionosphere, the electron pressure gradient term enhances the coupling of magnetosphere ionosphere. The electron pressure gradient can also generate the dynamic Alfven wave. It is supposed that this Alfven wave may change the velocity of particles.
