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Title: A gyro-gauge independent minimal guiding-center reduction by Lie-transforming the velocity vector field

We introduce a gyro-gauge independent formulation of a simplified guiding-center reduction, which removes the fast time-scale from particle dynamics by Lie-transforming the velocity vector field. This is close to Krylov-Bogoliubov method of averaging the equations of motion, although more geometric. At leading order, the Lie-transform consists in the generator of Larmor gyration, which can be explicitly inverted, while working with gauge-independent coordinates and operators, by using the physical gyro-angle as a (constrained) coordinate. This brings both the change of coordinates and the reduced dynamics of the minimal guiding-center reduction order by order in a Larmor radius expansion. The procedure is algorithmic and the reduction is systematically derived up to full second order, in a more straightforward way than when Lie-transforming the phase-space Lagrangian or averaging the equations of motion. The results write up some structures in the guiding-center expansion. Extensions and limitations of the method are considered.
Authors:
;  [1] ;  [2]
  1. Centre de Physique Théorique, Aix-Marseille Université, CNRS, UMR 7332, 13288 Marseille (France)
  2. (France)
Publication Date:
OSTI Identifier:
22227907
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physics of Plasmas; Journal Volume: 20; Journal Issue: 8; Other Information: (c) 2013 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; COORDINATES; EQUATIONS OF MOTION; LAGRANGIAN FUNCTION; LARMOR RADIUS; LIE GROUPS; PHASE SPACE; TRANSFORMATIONS; VECTOR FIELDS