The magnetic fluxes generated by the eddy currents were reconstructed with high accuracy using an inverse analysis technique in JT-60SA. This technique is based on the reconstruction of the magnetic fluxes using the external magnetic sensor signals and does not require preliminarily the precise position of the conducting structures. The plasma breakdown magnetic field has been successfully optimized in a situation where the position and shape of the conducting structures were not exactly known. This method optimizes logically the breakdown magnetic field and thus reduces efficiently the time required to achieve successful breakdown compared to the conventional experimental approach.
Setup and initial results from the magnetic flux surface diagnostics at Wendelstein 7-X