Finite-beta equilibria for Wendelstein 7-X configurations using the Princeton Iterative Equilibrium Solver code
- Max-Planck-Institut fuer Plasmaphysik, Teilinstitut Greifswald, EURATOM Association, Walther-Rathenau-Strasse 49 a, D-17489 Greifswald (Germany)
- Princeton Plasma Physics Laboratory, P. O. Box 451, Princeton, New Jersey 08543 (United States)
Fixed- and free-boundary equilibria for Wendelstein 7-X (W7-X) [W. Lotz {ital et al.}, {ital Plasma Physics and Controlled Nuclear Fusion Research 1990} (Proc. 13th Int. Conf. Washington, DC, 1990), (International Atomic Energy Agency, Vienna, 1991), Vol. 2, p. 603] configurations are calculated using the Princeton Iterative Equilibrium Solver (PIES) [A. H. Reiman {ital et al.}, Comput. Phys. Commun., {bold 43}, 157 (1986)] to deal with magnetic islands and stochastic regions. Usually, these W7-X configurations require a large number of iterations for PIES convergence. Here, two methods have been successfully tested in an attempt to decrease the number of iterations needed for convergence. First, periodic sequences of different blending parameters are used. Second, the initial guess is vastly improved by using results of the Variational Moments Equilibrium Code (VMEC) [S. P. Hirshmann {ital et al.}, Phys. Fluids {bold 26}, 3553 (1983)]. Use of these two methods have allowed verification of the Hamada condition and tendency of {open_quotes}self-healing{close_quotes} of islands has been observed. {copyright} {ital 1999 American Institute of Physics.}
- OSTI ID:
- 335596
- Journal Information:
- Physics of Plasmas, Vol. 6, Issue 4; Other Information: PBD: Apr 1999
- Country of Publication:
- United States
- Language:
- English
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