Magnetic analysis of plasma configuration in tokamak experiment using boundary element method

A method of magnetic analysis has been developed for experimental study of tokamak plasma configuration. The boundary element method has been applied to the determination of the magnetic flux distribution in a region bounded by magnetic sensors. The plasma cross-sectional shape is obtained without the difficulties that arise in the evaluation of the effects of the iron core of the transformer or of the eddy currents if they are excluded from the poloidal region encircled by magnetic sensors. The accuracy and validity of this method is checked by means of a comparison with numerically obtained MHD equilibria. The results have shown that the location of the plasma surface positions have been identified with an error of several percent of the plasma minor radius. This method has been applied to the analysis of the HT-2 experiment. Fairly good agreement is obtained between the magnetic analysis and limiter potential measurements. (author)