17,940 research outputs found
Noether derivation of exact conservation laws for dissipationless reduced-fluid models
The energy-momentum conservation laws for general reduced-fluid (e.g.,
gyrofluid) models are derived by Noether method from a general reduced
variational principle. The reduced canonical energy-momentum tensor (which is
explicitly asymmetric and has the Minkowski form) exhibits polarization and
magnetization effects associated with dynamical reduction. In particular, the
asymmetry in the reduced canonical momentum-stress tensor produces a
non-vanishing reduced intrinsic torque that can drive spontaneous toroidal
rotation in axisymmetric tokamak plasmas.Comment: 12 page
A guiding-center Fokker-Planck collision operator for nonuniform magnetic fields
A new formulation for collisional kinetic theory is presented based on the
use of Lie-transform methods to eliminate fast orbital time scales from a
general bilinear collision operator. As an application of this new formalism, a
general guiding-center bilinear Fokker-Planck (FP) collision operator is
derived following the elimination of the fast gyromotion time scale of a
charged particle moving in a nonuniform magnetic field. It is expected that
classical transport processes in a strongly magnetized nonuniform plasma can,
thus, be described in terms of this reduced guiding-center FP kinetic theory.
The present paper introduces the reduced-collision formalism only while its
applications are left to future work.Comment: 21 pages, Latex, to appear in Physics of Plasma
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