Feasibility of fuel-ion temperature and density profile diagnostics Using a neutron spectroscopic camera in JT‑60SA

A new diagnostic method for reconstructing fuel-ion temperature and density profiles using a neutron spectroscopic camera (NSC) is proposed. The method uses the Tikhonov-Phillips regularization to reconstruct these profiles from a set of line-integrated neutron energy spectra measured with the NSC camera. The validity of the method is examined using synthetic neutron signals under the JT-60SA deuterium plasma conditions calculated with an integrated simulation code GOTRESS+. The results show that both deuteron temperature and density profiles can be accurately reconstructed in the case that the Laplacian matrix is used in the regularization. The applicable range is identified by testing various profile shapes. The reconstructed profiles are found to agree well with the original profiles for relatively high temperature and density conditions, indicating that the method is well suited for diagnostics in the plasma core. The required measurement time for a proof-of-principle demonstration in future JT‑60SA experiments is assessed. The results suggest that the demonstration is feasible by accumulating measurement data from a single discharge or from several discharges under identical conditions.