Measurements of excitation rate coefficients for Al-like ions: Fe XIV, Ni XVI, and Cu XVII

Absolute excitation rate coefficients for Fe XVI and Ni xvi ions ions are measured spectroscopically in the Texas Experimental Tokamak. Previous measurements for the 3d-3p transition array of Cu XVII are verified and the measurements are extended to the 3s3p/sup 2/..-->..3s/sup 2/3p transition array of this ion. The experimental rate coefficient for the 3d-3p transition array of Fe XIV is 6.2 x 10/sup -9/ cm/sup 3/ s/sup -1/ at an electron temperature near 160 eV and for Ni XVI and Cu XVII, the values are 4.2 x 10/sup -9/ and 3.8 x 10/sup -9/ cm/sup 3/ s/sup -1/, respectively, at an electron temperature near 240 eV. For the 3s3p/sup 2/ /sup 2/P/sub 3/2/..-->..3s/sup 2/3p /sup 2/P/sub 3/2/ transition array, the experimental excitation rate coefficient for Fe XIV is 8.2 x 10/sup -9/ cm/sup 3/ s/sup -1/ at an electron temperature near 160eV and for Ni XVI and Cu XVII the value is 5.5 x 10/sup -9/ cm/sup 3/ s/sup -1/ at an electron temperature near 240 eV. The uncertainty in these results is estimated to be +- 50% (one standard deviation). Computed values of absolute excitation rates in a distorted-wave approximation and Mewe's semiempirical formula are found to be inmore » good agreement with the experimental values.« less