Collisional-Radiative models for hydrogen-like and helium-like carbon and oxygen ions and applications to experimental data from the TS tokamak and the reversed field pinch RFX

Abstract

Collisional radiative models (CRM) are needed to simulate experimental line brightnesses and emissivities from fusion devices. CRM are built for H-like and He-like carbon and oxygen ions, following a detailed review of the published literature on the required atomic data (including both collision rate coefficients and atomic transition probabilities). The impurity ion radial distribution is obtained using a transport code with two radius dependent transport parameters: a diffusion coefficient D and an inward convection velocity V. Reliable atomic data are a prerequisite to these simulations, since they are supposed to be well known; adjustement of the simulations to the experimental line and/or continuum brightnesses and emissivities is done by varying only D and V. Examples are given of the quantitative interpretation of experimental spectroscopic data from two fusion devices: the Tore Supra Tokamak and the Reversed Field Pinch RFX. As a consequence of the order of magnitude difference in the central electron temperatures in the two devices, the sensitivity of the H-like and He-like ion emissions to the transport parameters is different. These differences are highlighted in the examples given.