The effective ionization and recombination rate coefficients Ar xii–xvi were obtained by studying the modulation of line emission by sawtooth oscillations in the Texas Experimental tokamak (TEXT). Experimental data are matched with the simulation of argon ion emission by a one-dimensional code. The rate coefficients were determined for $T_e$∼400 eV and $N_e$∼4×${10}^{13}$ ${\mathrm{cm}}^{\mathrm{-}3}$. The uncertainty of ionization rates is estimated to be less than 30%, while the accuracy of the recombination rates is better than a factor of 2.

• Received 16 March 1987

DOI:https://doi.org/10.1103/PhysRevA.36.951