On the effects of missing chords and systematic errors on a new tomographic method for JET bolometry

Abstract

Abstract The accurate quantification of the emitted radiation is an important element in the interpretation of Tokamak performance and in the design of experiments. The spatial distribution of the total emitted radiation is typically determined with quite sophisticated tomographic techniques. On JET, a new tomographic inversion method, based on the Maximum Likelihood, has been very recently developed for this purpose. Its main innovative aspect is the analytic estimate of the confidence intervals in the emitted radiation levels. The present paper shows that the method is able to provide a reliable evaluation of the uncertainties of reconstructions. The impact of the data uncertainties on the reconstructed emissivity distributions in important regions of the main chamber is also evaluated. The resilience of the results in case of missing LOS is also analysed. The method is computationally quite fast and can therefore be applied on a routine basis.