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Tearing instability in an anisotropic neutral sheet

Journal Article · · Phys. Fluids; (United States)
DOI:https://doi.org/10.1063/1.864727· OSTI ID:7183461

A study is made of the collisionless tearing-mode stability properties of a neutral sheet whose temperature distribution is anisotropic. A kinetic description is used for both ions and electrons. The wave vector k of the perturbation is taken to be parallel to the equilibrium magnetic field B/sub 0/ and perpendicular to the equilibrium current J/sub 0/. The analysis is carried out for the low-frequency perturbation (Vertical Bar..omega..Vertical Bar<<..omega../sub c/i). It is found that the conventional technique of matching the inner and outer asymptotic solutions at the electron inner region (two-region approximation), thus neglecting the axis-crossing ion orbits outside the electron inner region, is inadequate for the anisotropic case. An intermediate region in which the axis-crossing ion orbits make the dominant contribution is identified. The eigenvalue equation is solved using both analytic approximations and numerical methods to obtain the eigenmode structure and the linear dispersion relation. Specializing primarily to anisotropic ions with isotropic or weakly anisotropic electrons, it is shown that inclusion of the ion intermediate region can enhance the growth rate by one order of magnitude over the conventional isotropic and anisotropic results based on the neglect of the ion intermediate region.

Research Organization:
Science Applications, Inc., McLean, Virginia 22101
OSTI ID:
7183461
Journal Information:
Phys. Fluids; (United States), Journal Name: Phys. Fluids; (United States) Vol. 27:5; ISSN PFLDA
Country of Publication:
United States
Language:
English