Speaker
Tamara Andreeva
(Max-Planck-Institut fuer Plasmaphysik)
Description
Wendelstein 7-X (W7-X), went into operation in December 2015 at the Max-Planck-Institut für Plasmaphysik in Greifswald, Germany, is a modular advanced stellarator with a magnetic field optimized for good plasma confinement and stability [1].
The magnet system of W7-X consists of 70 superconducting coils - ten non-planar and four planar in each out of five modules of the machine. Preliminary simulations of the plasma equilibrium properties were performed taking into account as-designed shapes and positions of W7-X coils. In these calculations each coil was represented by one filament subdivided in 96 cross-sections. As-built positions of coil filaments might considerably deviate from their as-designed values due to manufacturing and positioning tolerances or due to coil deformations under different kinds of loads.
Step-by-step evaluation of the magnet system geometry during the machine construction included measurements of the winding pack geometry in eight points characterising deviations of each coil cross-section caused by the fabrication process as well as the tracking of coil positions during main assembly steps [2]. In addition finite element calculations were performed with help of the 360° ANSYS Global Model in order to define possible coil deformations under the dead-weight, cool-down and electromagnetic loads in different operation regimes.
This presentation shows the comparative analysis of different types of deviations in the coil geometry and discusses their influence on plasma equilibrium properties, which allows to define a reliable basis for the detailed analysis of different diagnostic data.
References
[1] GRIEGER, G., et al., “Modular stellarator reactors and plans for Wendelstein 7–X”, Fusion Technol. 21 (1992) 1767-1778
[2] BRAEUER, T., et al., “Interaction of Metrology and Assembly at W7-X”, IEEE Transactions on Plasma Science, Vol. 42, No. 7, (2014).
Co-authors
Henning Thomsen
(Max-Planck-Institut fuer Plasmaphysik, Wendelsteinstrasse 1, 17491 Greifswald, Germany)
Joachim Geiger
(Max-Planck-Institut fuer Plasmaphysik, Wendelsteinstrasse 1, 17491 Greifswald, Germany)
Joris Fellinger
(Max-Planck-Institut fuer Plasmaphysik, Wendelsteinstrasse 1, 17491 Greifswald, Germany)
Michael Endler
(Max-Planck-Institut fuer Plasmaphysik, Wendelsteinstrasse 1, 17491 Greifswald, Germany)
Michael Grahl
(Max-Planck-Institut fuer Plasmaphysik, Wendelsteinstrasse 1, 17491 Greifswald, Germany)
Sergey Bozhenkov
(Max-Planck-Institut fuer Plasmaphysik, Wendelsteinstrasse 1, 17491 Greifswald, Germany)
Tamara Andreeva
(Max-Planck-Institut fuer Plasmaphysik, Wendelsteinstrasse 1, 17491 Greifswald, Germany)
Thomas Klinger
(Max-Planck-Institut fuer Plasmaphysik, Wendelsteinstrasse 1, 17491 Greifswald, Germany)
Victor Bykov
(Max-Planck-Institut fuer Plasmaphysik, Wendelsteinstrasse 1, 17491 Greifswald, Germany)
