April 15-17

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Abstracts

Author: Ian G Abel
Requested Type: Poster
Submitted: 2019-02-22 15:16:30

Co-authors: S. C. Cowley, A. K. Thackray

Contact Info:
University of Maryland
8279 Paint Branch Drive
College Park, Maryland   20742-3
USA

Abstract Text:
Hot plasmas are fantastically good electrical conductors. This
property has many important consequences -- the motion of the plasma and the motion of lines of magnetic force are tightly coupled. This radically restricts the possible motions of both the plasma and the field lines. One potential relaxation of these restrictions comes through the effect of the very small resistivity, when it is amplified by sharp gradients in the magnetic field.
Such gradients arise due to plasma motions and are amplified by the presence of inhomogeneities in the magnetic field -- in particular magnetic shear.

Filaments of hotter plasma, moving past cooler plasma, are an important method by which heat is transported in magnetized plasmas. Thus, a deep understanding of how field lines can move in a weakly-resistive plasma is need. In order to understand complex plasma eruptions, be they ELMs or solar flares, we study a paradigmatic and much simpler problem. The motion of field lines in a pressure-free slab of sheared plasma.

We study the small-amplitude motions of a field line upon which a force is exerted. The motion of such field lines in both linearly-sheared and exponentially-sheared geometries is considered. The latter are important for understanding the motion of field lines in a turbulent medium or near a separatrix at the edge of a plasma.

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