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Author(s):
H. Sugama, T.-H. Watanabe, M. Nunami and S. Nishimura
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Title:
Quasisymmetric Toroidal Plasmas with Large Mean Flows
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Date of publication:
July 27, 2011
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Key words:
quasisymmetry, plasma flows
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Abstract:
Geometric conditions for quasisymmetric toroidal plasmas with large mean flows on the order of the ion thermal speed are investigated. Equilibrium momentum balance equations including the inertia term due to the large flow velocity are used to show that, for rotating quasisymmetric plasmas with no local currents crossing flux surfaces, all components of the metric tensor should be independent of the toroidal angle in the Boozer coordinates, and consequently these systems need to be rigorously axisymmetric. Unless the local radial currents vanish, the Boozer coordinates do not exist and the toroidal flow velocity cannot take any value other than a very limited class of eigenvalues corresponding to very rapid rotation especially for low beta plasmas.
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