Modeling of the L and M x-ray line structures for tungsten in high-temperature tokamak plasmas

Abstract

We present the results of modeling of the L and M x-ray line structures for tungsten in high-temperature plasmas predicted with temperatures relevant to large tokamaks including the Joint European Tokamak and the future International Thermonuclear Experimental Reactor. The simulations have been performed using the Flexible Atomic Code within the framework of the collisional–radiative (CR) model. For L x-ray lines, our results predicted for various levels of CR model sophistication have been compared with the spectrum measured using the electron beam ion trap (EBIT) calorimeter spectrometer at the Livermore SuperEBIT that constitutes a rigorous atomic benchmark for tokamak plasmas. In the case of M x-ray lines, we have reproduced the experimental SuperEBIT spectra as a superposition of theoretical contributions for different ions. The obtained results enable us to propose an approach allowing the decomposition of registered experimental tungsten spectra produced in tokamaks into the theoretically predicted contributions, corresponding to different degrees of ionization.