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Electromagnetic and Linear Structural Analysis of the National Compact Stellarator Experiment (NCSX) Modular Coil System

Leonard Myatt, D. E. Williamson, H. M. Fan

Fusion Science and Technology / Volume 47 / Number 4 / May 2005 / Pages 916-920

Technical Paper / Fusion Energy - Fusion Materials

A detailed electromagnetic-structural ANSYS analysis of the NCSX Modular Coil (MC) system is presented. The simplified (linear) model is used to provide some insights into the essential behavior of the modular coil. In the actual device, the winding packs are Vacuum Pressure Impregnated (VPI'd) in-place and restrained by 50+ clamps per coil. In general, JxB Lorentz forces press the winding pack (WP) onto the structure which makes the linear (''glued'') approach justifiable. The benefit, of course, is relatively fast computer run-times and a modeling tool which is able to perform numerous design studies. However, there are regions where the electromagnetic (EM) forces point away from the structure and locally invalidate the glued approximation.

The results of a variety of design studies are presented, such as the structural stiffness and worst case running loads at the poloidal breaks, non-ideal coil center displacements from thermal contractions and structural loads, smeared winding pack and winding form stresses, and the effects of supporting the convoluted MC ''wings'' with the neighboring shell. Critical results are illustrated with contour plots, and where possible, compared to the NCSX structural design criteria.

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