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In the fifth W7-X workshop the reference design chosen in the W7-X proposal was changed in minor detail only, and substantially improved with respect to the space available for a divertor and the critical coil curvature. In W7-X the magnetic field is produced by 50 poloidally closed nonplanar coils distributed in five identical modules, i.e., five field periods. In order to give operational flexibility to the device 20 additional noncircular planar coils are mounted over the modular coil system. In the standard configuration, all currents are identical in the nonplanar coils and zero in the planar ones. Modifications of this configuration are obtained either by energising the planar coils (to produce low or high rotational transform, inward or outward shift of the magnetic axis), or by energising each of the five groups of identical nonplanar coils with slightly different currents (to produce low or high mirror ratio, low or high shear). Conventional NbTi superconductor technology has been chosen to allow a stationary magnetic field which allows long-pulse plasma operation up to 30 s. Normal- conducting sweep coils are considered for fine-tuning of the configuration (island size and position, error fields) and of divertor heat loads, if required. The intended plasma parameters are central ion and electron temperatures of 2-5 keV and a central density up to 2 x 1.0 E20/m3. Estimated energy confinement times range between 0.1 and 0.5 s. The nineteen papers presented at this workshop cover topics such as the boundary region, SOL, divertor plates, sweep coil system and neutral injection.

Additional information

Authors: RAU F (EDITOR), Max-Planck-Institut für Plasmaphysik, Garching bei München (DE)
Bibliographic Reference: Report: IPP 2/317 EN (1992) 156 pp.
Availability: Available from Max-Planck-Institut für Plasmaphysik, 8046 Garching bei München (DE)
Record Number: 199211263 / Last updated on: 1994-11-29
Original language: en
Available languages: en