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Title: Enhanced magnetic reconnection in the presence of pressure gradients

Magnetic reconnection in the presence of background pressure gradients is studied, with special attention to parallel (compressional) magnetic fluctuations. A process is reported that reconnects fields through coupling of drift-wave-type instabilities with current sheets. Its time scale is set not by the reconnecting field but by inhomogeneities of the background density or temperature. The observed features can be attributed to a pressure-gradient-driven linear instability which interacts with the reconnecting system but is fundamentally different from microtearing. In particular, this mode relies on parallel magnetic fluctuations and the associated drift. For turbulent reconnection, similar or even stronger enhancements are reported. In the solar corona, this yields a critical pressure gradient scale length of about 200 km below which this new process becomes dominant over the tearing instability.
Authors:
;  [1] ; ;  [2] ;  [3]
  1. Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States)
  2. Max-Planck-Institut für Plasmaphysik, D-85748 Garching (Germany)
  3. (United States)
Publication Date:
OSTI Identifier:
22410430
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 22; Journal Issue: 6; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; CRITICAL PRESSURE; FLUCTUATIONS; MAGNETIC RECONNECTION; PRESSURE GRADIENTS; SHEETS; SOLAR CORONA; TEARING INSTABILITY; WAVE PROPAGATION