Intuitive Approach to Magnetic Reconnection
Authors: Russell M. Kulsrud
Abstract:
Two reconnection problems are considered. The first problem concerns global physics. The plasma in the global reconnection region is
in magnetostatic equilibrium. It is shown that this equilibrium can be uniquely characterized by a set of constraints. During reconnection
and independently of the local reconnection physics, these constraints can be uniquely evolved from any initial state. The second problem
concerns Petschek reconnection. Petschek's model for fast reconnection, which is governed by resistive MHD equations with constant resistivity, is not validated by numerical simulations. Malyshkin, Linde, and Kulsrud (2005), showed that the reason for the discrepancy is that
Petschek did not employ Ohm's law throughout the local diffusion region, but only at the X-point. A derivation of Petschek reconnection,
including Ohm's law throughout the entire diffusion region, removes the discrepancy. This derivation is based largely on Petschek's original 1964 calculation (Petschek 1964). A useful physical interpretation of the role which Ohm's law plays in the diffusion region, is presented.
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Submitted to: Physics of Plasmas, (March, 2011)
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Download PPPL-4681 (pdf 266 KB 16 pp)
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