Eddy current analysis in JT-60

In response to the demands from a mechanical design and a control analysis of plasma position, current and shape, intensive numerical and analytical eddy current studies have been made in JT-60 project. The numerical results of eddy current analysis in JT-60 multi-torus system using the numerical code EDDYMULT which was newly developed in JAERI are presented. Taking into account the mutual coupling between a vacuum vessel, toroidal coils, support plates and a central column, the eigen functions of eddy current defined in the entire multi-torus system were obtained by the method of modal analysis. In order to confirm the validity of our numerical code, the model experiments were carried out and satisfactory agreement between the experimental and the numerical results was obtained. Volt-second loss of ohmic heating circuit due to the eddy current and the transient shape of equilibrium field including the eddy current field during regular start-up of plasma were numerically calculated in JT-60 multi-torus system. The application to the advanced study based on a modern control theory was discussed in particular on controlling a plasma position including the eddy current effect in the actual geometry. (author)