New aspects of plasma sheet dynamics – MHD and kinetic theory

H. Wiechen
1999 Annales Geophysicae  
Magnetic reconnection is a process of fundamental importance for the dynamics of the Earth's plasma sheet. In this context, the development of thin current sheets in the near-Earth plasma sheet is a topic of special interest because they could be a possible cause of microscopic¯uctuations acting as collective non-idealness from a macroscopic point of view. Simulations of the near-Earth plasma sheet including boundary perturbations due to localized in¯ow through the northern (or southern) plasma
more » ... or southern) plasma sheet boundary show developing thin current sheets in the near-Earth plasma sheet about 8±10 i tailwards of the Earth. This location is largely independent from the localization of the perturbation. The second part of the paper deals with the problem of the macroscopic non-ideal consequences of microscopic uctuations. A new model is presented that allows the quantitative calculation of macroscopic non-idealness without considering details of microscopic instabilities or turbulence. This model is only based on the assumption of a strongly¯uctuating, mixing dynamics on microscopic scales in phase space. The result of this approach is an expression for anomalous non-idealness formally similar to the Krook resistivity but now describing the macroscopic consequences of collective microscopic¯uctuations, not of collisions.
doi:10.1007/s005850050787 fatcat:n6kznfbm3jbh3pdevvt2tavn6m