A mesh-generation scheme for the Large Helical Device based on the structure of magnetic-field lines

We report herein an automated scheme for generating a mesh based on a structure of magnetic-field lines. For all angles in the toroidal subdomain, the mesh generated by this scheme must not contain broken tetragons. To satisfy this requirement, we propose herein a first method to detect broken elements and a second method to automatically modify the broken elements. We use the proposed mesh-generation scheme with magnetic-field data acquired on the magnetic axis of the Large Helical Device at R_ax = 3.75 m. The results show that broken elements are detected by the first method, and the second method transforms broken elements into regular elements. (author)