Experimental and simulated neon spectra in the 10-nm wavelength region from tokamak and reversed held pinch plasmas

Experimental neon spectra (in the 10-nm region), from the tokamak Tore Supr a and the reversed field pinch experiment RFX, have been simulated. The spe ctra include lines from three neon ionization states, namely Ne7+, Ne6+, an d Ne5+ ions. Collisional radiative models have been built for these three N e ions, considering electron collisional excitation and radiative decay as populating processes of the excited states. These models give photon emissi on coefficients for the emitted lines at electron density and temperature v alues corresponding to the experimental situations. Impurity modelling is p erformed using a one-dimensional impurity transport code, calculating the s teady-state radial distribution of the Ne ions. The Ne line brightnesses ar e evaluated in a post-process subroutine and simulated spectra are obtained . The parts of the spectra corresponding to a single ionization state do no t depend on the experimental conditions and show good agreement with the si mulated single ionization state spectra. On the other hand, the superpositi on of the three spectra depends on the experimental conditions, as a conseq uence of the fact that the ion charge distribution depends not only on the radial profiles of the electron density and temperature, but also of the im purity transport coefficients. Simulations of the Ne spectra (including tra nsport) give confidence in the atomic physics calculations; moreover, they allow the determination of the transport coefficients in the plasma region emitting the considered ionization states. [S1063-651X(99)14510-0].