Three Dimensional Structure of the Electron and Ion Scales of Reconnection
Abstract:We have investigated the location and extent of magnetic reconnection in a realistic magnetotail configuration by using a combination of the UCLA global MHD simulation of the solar wind, magnetosphere and ionosphere system and the iPIC3D large scale particle in cell simulation. In this approach we first run a global MHD simulation driven by upstream solar wind observations. Then we use the results from the MHD simulation to set the initial and boundary conditions for the large scale 3D PIC simulation. The evolution of the system is constrained by the initial MHD state but evolves fully kinetically. The electrons and ions are followed in fields determined by using Maxwell’s equations. This approach combines both macro-MHD and small-kinetic scales in a single numerical simulation.
For many studies the magnetotail can be thought of as invariant in the dawn dusk or Y direction. However, in many other situations the tail is kinked and/or flaps in time and one cannot assume invariance in the Y direction. We report an investigation of a case where the structure of the tail varies significantly in the Y-direction and a PIC simulation in a realistic configuration is necessary. We have found that the reconnection electric field and the ion outflow jet regions expand in Y. But the reconnection region remains localized and is accompanied by a narrow electron jet with a Y-extent comparable to an ion skin depth. This narrow jet does not show any sign of expanding in Y, but remains narrow despite the wider ion scale. Implications for the MMS mission will be discussed.