Inversion techniques to obtain local rotation velocity and ion temperature profiles for the x-ray crystal spectrometer on EAST

Abstract

Inversion techniques are conducted based on the tangential x-ray crystal spectroscopy (TXCS) geometry on EAST to obtain the local profiles of ion temperature (T i) and toroidal rotation velocity (v t). Firstly, local emissivity profiles of the impurity argon are obtained using the asymmetrical Abel inversion. Then, the local v t and T i profiles are calculated by considering the local emissivity profiles and the TXCS detailed geometry. In addition, how the changes in the v t profiles affect the accuracy in the T i profiles is discussed in detail. It is also found that the line-integrated T i profiles are becoming less accurate with the increase in the radial gradient in the local v t profiles. Nonetheless, accurate T i radial profiles are reconstructed after considering the effects of the emissivity and velocity, which are verified by comparing the inverted v t and T i profiles with those local profile measurements from the Charge eXchange Recombination Spectroscopy (CXRS) on EAST.