Error estimation and parameter dependence of the calculation of the fast ion distribution function, temperature, and density using data from the KF1 high energy neutral particle analyzer on Joint European Torus

Joint European Torus high energy neutral particle analyzer measures the flux of fast neutrals originating from the plasma core. From this data, the fast ion distribution function fifast, temperature Ti,perpendicularfast, and density nifast are derived using knowledge of various plasma parameters and of the cross section for the required atomic processes. In this article, a systematic sensitivity study of the effect of uncertainties in these quantities on the evaluation of the neutral particle analyzer fifast, Ti,perpendicularfast, and nifast is reported. The dominant parameter affecting nifast is the impurity confinement time and therefore a reasonable estimate of this quantity is necessary to reduce the uncertainties in nifast below 50%. On the other hand, Ti,perpendicularfast is much less sensitive and can certainly be provided with an accuracy of better than 10%