Magnetic field lines, Hamiltonian dynamics, and nontwist systems
- Department of Physics and Institute for Fusion Studies, University of Texas at Austin, Austin, Texas 78712 (United States)
Magnetic field lines typically do not behave as described in the symmetrical situations treated in conventional physics textbooks. Instead, they behave in a chaotic manner; in fact, magnetic field lines are trajectories of Hamiltonian systems. Consequently the quest for fusion energy has interwoven, for 50 years, the study of magnetic field configurations and Hamiltonian systems theory. The manner in which invariant tori breakup in symplectic twist maps, maps that embody one and a half degree-of-freedom Hamiltonian systems in general and describe magnetic field lines in tokamaks in particular, will be reviewed, including symmetry methods for finding periodic orbits and Greene's residue criterion. In nontwist maps, which describe, e.g., reverse shear tokamaks and zonal flows in geophysical fluid dynamics, a new theory is required for describing tori breakup. The new theory is discussed and comments about renormalization are made. (c) 2000 American Institute of Physics.
- OSTI ID:
- 20216536
- Journal Information:
- Physics of Plasmas, Vol. 7, Issue 6; Other Information: PBD: Jun 2000; ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
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