C III Emission Lines in Ionizing and Recombining Plasmas

Abstract

In plasmas the population densities are affected by electron collisions and by photon emission and absorption. In low temperature plasmas such as divertor or process plasmas, emissions from impurities are important for plasma diagnostics and plasma modeling. We study the density effect on population densities, effective ionization and recombination rate coefficients and emission lines from carbon ions. Especially we studied recombination processes for L-shell carbon ions because atomic data for dielectronic recombination for L-shell ions have recently become available. We made collisional radiative (CR) models for carbon L-shell ions including both ionization/excitation and recombination processes. Our CR model can calculate the line emission associated with recombination as well as that associated with excitation. In this work we apply these models to measured spectra from LHD (Large Helical Device) in the National Institute for Fusion Science. The spectra in recombining phase are measured in LHD and they are compared with our CR model.