Research on algorithms for wire-grid tomography in the CN-H1 stellarator

Wire Tomography is a high-precision and high-resolution method for mapping the vacuum magnetic field configuration on the CN-H1 Stellarator , prioritized for reconstruction during the restoration of the CN-H1 Stellarator. The diagnostic principle involves emitting an electron beam from an electron gun, which is then received by a wire-grid detector positioned at specified locations through stepwise rotation. This system outputs current data captured by molybdenum wires on the wire-grid detector at each rotational angle. Using tomographic inversion algorithms, these data are reconstructed into the magnetic field configuration on the wire-grid detector plane. Based on existing diagnostic hardware and its principles, this study establishes a diagnostic model to simulate projection function data of electron trajectories onto the rotating wire-grid detector. The projection data are then reconstructed using the Multiplicative Algebraic Reconstruction Technique (MART) algorithm. A comparison between the reconstructed image and the magnetic field configuration map demonstrates close alignment in both flux surface geometry and spatial resolution, validating the accuracy of the tomographic reconstruction in resolving vacuum magnetic topology.