COMPUTATION OF MHD EQUILIBRIA BY A QUASI-INVERSE FINITE HYBRID ELEMENT APPROACH
To supply a precise and consistent solution of the Grad-Schlueter-Shafranov equation to the ideal linear MHD stability code ERATO, a quasi-inverse finite hybrid element code has been written. To fit well the plasma surface and the region around the magnetic axis, adequate coordinate transformations are made. A Picard iteration is used to treat the non-linearity of the source term. One Picard step is carried out by solving the weak form of the partial differential equation by an isoparametric finite hybrid element approach (FHE). After each Picard step, the nodal points are re-adjusted such that they fall on initially prescribed flux surfaces. This enables us to accumulate the nodal points in those regions where good precision is needed for the stability code. While for a conforming finite element scheme a 4-point integration is necessary, a 1-point integration is sufficient in a FHE approach. Coding the FHE is very simple and easily vectorizable. For a given resolution, the precision of global quantities, such as the total flux, is the same for both methods but the FHE approach is faster.
Bibliographic Reference: WRITE TO CONFEDERATION SUISSE, CENTRE DE RECHERCHES EN PHYSIQUE DES PLASMAS, ECOLE POLYTECHNIQUE FEDERALE DE LAUSANNE, 21, AVENUE DES BAINS, CH-1007 LAUSANNE (SWITZERLAND), MENTIONING REPORT LRP E 271/85, 1986
Record Number: 1989124099300 / Last updated on: 1987-01-01
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