Analysis of the Accuracy of Measuring the Flux Density of All Hydrogen Isotopes from First Wall to Plasma Using the H-Alpha Diagnostics in ITER

The results of the analysis of the accuracy of measuring the flux density of all hydrogen isotopes from the first wall of the main vacuum chamber to the ITER tokamak plasma using the high-resolution spectroscopy of Balmer alpha lines of hydrogen isotopes (H-alpha diagnostics) are presented. Under the conditions of the expected high background radiation generated by the divertor stray light and the absence of the possibility of using the optical dumps in ITER, a differential measurement scheme is necessary, which uses the spatial variation of the coefficient of the light reflection from the natural landscape of the first wall. The measurement accuracy analysis is carried out with the help of the method of synthetic diagnostics, which uses the results of the predictive numerical modeling of different modes of hydrogen recycling for simulation of the expected diagnostic signals and determination of the desired parameters by solving an inverse problem.