Electron density diagnostic potential of Ar XIV soft X-ray emission lines

Theoretical electron density-sensitive line ratios R₁-R₆ of Ar XIV soft X-ray emission lines are presented. We found that these line ratios are sensitive to the electron density n_e, and the ratio R₁ is insensitive to electron temperature T_e. Recent work has shown that accurate atomic data, such as electron impact excitation rates, is very important for an reliable determination of the electron density of laboratory and astrophysical plasmas. Present work indicates that the maximum discrepancy of line ratios introduced from different atomic data calculated with distorted wave and R-matrix approximations, is up to 18% in the range of . By comparison of these line ratios with experiment results carried out in electron beam ion trap (EBIT-II), electron density of the laboratory plasma is diagnosed, and a consistent result is obtained from R₁, R₂ and R₃. Our result is in agreement with that diagnosed by Chen et al. using triplet of N VI. A relative higher diagnosed electron density from R₂ is due to its weak sensitivity to electron temperature. A better consistency at lower T_e indicates that temperature of the laboratory plasma is lower than logT_e(K)=6.5. Comparison between the measured and theoretical ratios reveals that 32.014 Å  line is weakly blended by lines from other Ar ions, while 30.344 Å  line is strongly contaminated.