Electron density diagnostic for hot plasmas in coronal regime by using B-like ions

Abstract

Line ratio of $3d-2p$ transition lines in boron-like spectra of Si X, S XII, Ar XIV and Fe XXII has been investigated. Collisional-radiative model calculations reveal that the line ratio is sensitive to the electron density in ranges of $n_{\mathrm{e}}=4.0\times 10^7-3.0\times 10^{10}$ cm${}^{-3}$, $4.0\times 10^8-3.0\times 10^{11}$ cm${}^{-3}$, $3.0\times 10^9-4.0\times 10^{12}$ cm${}^{-3}$ and $2.0\times 10^{12}-3.0\times 10^{15}$ cm${}^{-3}$, respectively. This complements the K-shell diagnostics of helium-like ions. By comparison between the prediction and the measured values, effective electron densities in the electron beam ion trap (EBIT) plasmas performed by Lepson and collaborators at Lawrence Livermore EBIT, are estimated to be $n_{\mathrm{e}}=3.4_{-0.6}^{+0.8}\times 10^{10}$ cm${}^{-3}$ and $5.6_{-1.1}^{+1.0}\times 10^{10}$ cm${}^{-3}$ for sulphur and argon plasmas. In case of argon, a good agreement is shown with the actual electron density derived from N VI K-shell spectrum. We further explore the $3d-2p$ transition lines of Si X and S XII in the stellar coronal spectra measured with the Low Energy Transmission Grating Spectrometer combined with High Resolution Camera on board the {\it Chandra X-ray Observatory}. The constrained electron densities show a good agreement with the those determined from C V and O VII K-shell spectra.

15 pagess, 5 figures and 4 tables, accepted for publication on AJ

References in corpus (19)

• Collisional Plasma Models with APEC/APED: Emission Line Diagnostics of Hydrogen-like and Helium-like Ions
• Evidence for Accretion: High-Resolution X-ray Spectroscopy of the Classical T Tauri Star TW Hydrae
• Line ratios for Helium-like ions: Applications to collision-dominated plasmas
• X-ray emission from a metal depleted accretion shock onto the classical T Tauri star TW Hya
• Collisional Ionization Equilibrium for Optically Thin Plasmas. I. Updated Recombination Rate Coefficients for Bare though Sodium-like Ions
• On the sizes of stellar X-ray coronae
• High-resolution X-ray spectroscopy of Procyon by Chandra and XMM-Newton
• The Chandra Iron-L X-Ray Line Spectrum of Capella
• X-rays from accretion shocks in T Tauri stars: The case of BP Tau
• Helium-like triplet density diagnostics: Applications to CHANDRA--LETGS X-ray observations of Capella and Procyon
• Coronal density diagnostics with Helium-like triplets: CHANDRA--LETGS observations of Algol, Capella, Procyon, Eps Eri, Alpha Cen A&B, UX Ari, AD Leo, YY Gem, and HR1099
• Modeling the NeIX Triplet Spectral Region of Capella with the Chandra and XMM-Newton Gratings
• High-resolution X-ray spectroscopy of the evolving shock in the 2006 outburst of RS Ophiuchi
• Revisiting He-like X-ray Emission Line Plasma Diagnostics
• Chandra LETGS Observation of the Active Binary Algol
• Anomalous X-ray line ratios in the cTTS TW Hya
• Electron density diagnostic potential of Ar XIV soft X-ray emission lines
• Coronal density diagnostics with Si X: CHANDRA/LETGS observations of Procyon, $\alpha$ Cen A$&$B, Capella and $\epsilon$ Eri
• Determinations of temperature and density for solar-like Stars using Si XI soft X-ray emission lines