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Proposing Institution

Max-Planck-Institute for Solar System Research
Project Manager

Prof. Jörg Büchner
Justus-von-Liebig Weg 3
37077 Göttingen
Collisonless magnetic reconnection is supposedly the most efficient mechanism of magnetic energy conversion into plasma kinetic energy, heat and particle acceleration in the Universe. Its properties can be investigated {\it in situ}, however, only in the Earth's magnetosphere. For the first time the current high-resolution observations of the magnetospheric multi-spacecraft mission MMS now allows to resolve the electron kinetic plasma scales. This way in the turbulent high-beta plasma of the magnetosheath surrounding the Earth’s magnetosphere electron-scale thin current sheets where discovered which are assumed to undergo reconnection. Further asymmetric reconnection was discovered through the boundary of the magnetosphere, the magnetopause, through which plasmas of different origin are transported, which mix. These two discoveries are most relevant for astrophysical plasmas since they correspond to plasma and field conditions which are typical also for remote places in the Universe. The observations are, however, theoretically not well understood, yet. Their understanding requires fully kinetic numerical simulations which we plan to carry out in the framework of this proposal.In particular we are going to investigate the efficiency of reconnection through current sheets in turbulent high-beta plasmas as observed in the magnetosheath as well as the plasma transport through asymmetric current sheets in dependence on the plasma inflow conditions and compositions: In fact the properties of reconnection for large thermal (compared to the magnetic) pressure (high plasma-beta) are not well understood as well as reconnection through asymmetric current sheets. We will address these problems via 2.5 D Particle-in-Cell (PIC) code implementing appropriate parameters and geometries. This way we will not only contribute to the investigation of these newly discovered kinds of magnetic reconnection, providing theoretical support for ongoing and future {\it in-situ} measurements, but we will also improve the understanding of the basic physics of collisionless reconnection in a larger variety of astrophysical plasmas.

Impressum, Conny Wendler