Global Hybrid Simulation of the Magnetopause Boundary Layer in Low- and High-Latitude Magnetic Reconnections

Xie, H.; Lin, Y.; Perez, J.
Bibliographical reference

American Geophysical Union, Fall Meeting 2001, abstract #SM41B-0799

Advertised on:
12
2001
Number of authors
3
IAC number of authors
0
Citations
0
Refereed citations
0
Description
A 2-D global hybrid simulation is carried out to study the structure of the dayside magnetopause in the noon-midnight meridian plane associated with magnetic reconnection. In the simulation the bow shock, magnetosheath, and magnetopause are formed self-consistently by supersonic solar wind passing the geomagnetic field. The reconnection events at high- and low-latitudes are simulated for various IMF conditions. To assure the validation of the applied spatial resolution, we also compare this global-scale simulation with our previous 2-D hybrid simulations for the local magnetopause structure near the X line and the simulation of the corresponding 1-D Riemann problem. The following results will be presented. (1) Large-amplitude rotational discontinuities and Alfvén waves are present in the quasi-steady reconnection layer. (2) The rotational discontinuity possesses an electron sense, or right-hand polarization in the magnetic field as the discontinuity forms from the X line. Later, however, the rotational discontinuity tends to evolve to a structure with a smallest field rotational angle and thus may reverse its sense of the field rotation. The Walén relation is tested for electron and ion flows in the magnetopause rotational discontinuities with left-hand and right-hand polarizations. (3) The structure of the magnetopause discontinuities and that of the accelerated/decelerated flows are modified significantly by the presence of the local magnetosheath flow. (4) Field-aligned currents are generated in the magnetopause rotational discontinuities. Part of the magnetopause currents propagate with Alfvén waves along the field lines into the polar ionosphere, contributing to the field-aligned current system in the high latitudes. (5) Finally, typical ion velocity distributions will be shown at various locations across the magnetopause northward and southward of the X lines. The ion distributions associated with single or multiple X lines will be discussed. The transmission and reflection rates of the magnetosheath particles have also been calculated.