New tomographic reconstruction technique based on Laplacian eigenfunction

This letter proposes a new tomographic reconstruction procedure based on the Laplacian eigenfunction (LEF) patterns, which are independent of the plasma cross-section and do not require the flux surface information. The process is benchmarked for the experimental data of Heliotron J plasma and the results are compared with the least-squares approximation by a Phillips-Tikhonov (PT)-type regularization, which is widely used as the standard technique for tomographic reconstruction. The reconstruction based on the LEF is found to be capable of determining the magnetic axis at different time locations efficiently in comparison with the PT-type regularization.