Novel Design Methods for Magnetic Flux Loops in NCSX, the National Compact Stellarator Experiment
Authors: N. Pomphrey, E. Lazarus, M. Zarnstorff, A. Boozer, and A. Brooks
Abstract:
Magnetic pickup loops on the vacuum vessel (VV) can provide an abundance of equilibrium information for stellarators. A substantial effort has gone into designing flux loops for the National Compact Stellarator Experiment (NCSX) [Zarnstorff et al., Plasma Phys. Control. Fusion 43 A237 (2001)], a 3-field period quasi-axisymmetric stellarator under construction at Princeton Plasma Physics Laboratory (PPPL). The design philosophy, to measure all of the magnetic field distributions normal to the VV that can be measured, has necessitated the development of Singular Value Decomposition algorithms for identifying efficient loop locations. Fields are expected to be predominantly stellarator symmetric (SS) — the symmetry of the machine design — with toroidal modenumbers per torus, n, equal to a multiple of 3 and possessing reflection symmetry in a period. However, plasma instabilities and coil imperfections will generate non-SS fields which must also be diagnosed. The measured symmetric fields will yield important information on the plasma current and pressure profile as well as on the plasma shape.
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Published in: Physics of Plasmas 14, 056103 (May 2007) 12 pp
doi: 10.1063/1.2472368
Copyright (2007) American Institute of Physics.
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