Modification of SXB Method for Hydrogen in ITER Main Chamber

A modification of the SXB method, used for evaluating the atom/ion flux from the tokamak first wall into plasma using the observed wavelength-integrated spectral line intensity, is proposed. The modification allows, using the high-resolution spectroscopy data, to estimate — in real time measurements — the fluxes of atomic and molecular hydrogen from the first wall of the tokamak main chamber into plasma without measurements of molecular spectra. The modified SXB method is tested by comparing the results with the SOLPS code simulations for six modelled types of the SOL plasma profiles in ITER. The proposed modification is motivated by the fact that the hydrogen molecular spectra will not be used for ITER operation diagnostics because of difficulties of their interpretation.