Anatoly Nekrasov, Mohsen Shadmehri. Multicomponent theory of buoyancy instabilities in magnetized plasmas: The case of magnetic field parallel to gravity
Submitted on: Sep 10, 2012, 15:00:23
Natural Sciences / Astronomy / Astrophysics
Description: We investigate electromagnetic buoyancy instabilities of the electron-ion plasma with the heat flux based on not the magnetohydrodynamic (MHD) equations, but using the multicomponent plasma approach when the momentum equations are solved for each species. We consider a geometry in which the background magnetic field, gravity, and stratification are directed along one axis. The nonzero background electron thermal flux is taken into account. Collisions between electrons and ions are included in the momentum equations. No simplifications usual for the one-fluid MHD-approach in studying these instabilities are used. We derive a simple dispersion relation, which shows that the thermal flux perturbation generally stabilizes an instability for the geometry under consideration. This result contradicts to conclusion obtained in the MHD-approach. We show that the reason of this contradiction is the simplified assumptions used in the MHD analysis of buoyancy instabilities and the role of the longitudinal electric field perturbation which is not captured by the ideal MHD equations.
The Library of Congress (USA) reference page : http://lccn.loc.gov/cn2013300046.
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