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

Abstract

Theoretical electron density-sensitive line ratios $R_1-R_6$ of Ar XIV soft X-ray emission lines are presented. We found that these line ratios are sensitive to electron density $n_e$, and the ratio $R_1$ 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 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 $n_e=10^{9-13}$cm${}^{-3}$. 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 $R_1$, $R_2$ and $R_3$. Our result is in agreement with that diagnosed by Chen et al using triplet of N VI. A relative higher diagnosed electron density from $R_2$ 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 log$T_e$(K)=6.5. Comparison between the measured and theoretical ratios reveals that 32.014~Åline is weakly blended by lines from other Ar ions, while 30.344~Åline is strongly contaminated.

arXiv comment18 pages, 6 figures, published in J. Quan. Spec. Rad. Trans

References in corpus (10)

• First Light Measurements with the XMM-Newton Reflection Grating Spectrometers: Evidence for an Inverse First Ionisation Potential Effect and Anomalous Ne A bundance in the Coronae of HR 1099
• First Light Measurements of Capella with the Low Energy Transmission Grating Spectrometer aboard the Chandra X-ray Observatory
• High Resolution X-Ray Spectra of Capella: Initial Results from the Chandra High Energy Transmission Grating Spectrometer
• On the sizes of stellar X-ray coronae
• The Chandra Iron-L X-Ray Line Spectrum of Capella
• The Density of Coronal Plasma in Active Stellar Coronae
• Helium-like triplet density diagnostics: Applications to CHANDRA--LETGS X-ray observations of Capella and Procyon
• Modeling the NeIX Triplet Spectral Region of Capella with the Chandra and XMM-Newton Gratings
• Chandra High-Resolution X-Ray Spectrum of Supernova Remnant 1E0102.2-7219
• Chandra LETGS Observation of the Active Binary Algol

Cited by in corpus (2)

• Extreme Emission-Line Galaxies in SDSS. I. Empirical and model-based calibrations of chemical abundances
• Electron density diagnostic for hot plasmas in coronal regime by using B-like ions