Beam-foil spectroscopy in the 3–6 nm soft-X-ray range

Atomic data and spectral line intensities for Mg IX

“…The density sensitivity of the Mg IX lines is moderate at typical active region densities, and intensity ratios among lines from the 2s2p 3 P-2p 2 3 P multiplet can be used to measure plasma electron densities N e only below 10 9 cm À3 , so that only in quiet Sun conditions and outside the solar disk Table B Comparison between lifetimes (in 10 À10 s units) predicted by the present calculations and measured by Granzow et al [13] (G94), Träbert and Heckmann [11] (TH80), and Mö ller et al [12] can Mg IX lines be used for density diagnostics. Such ratios are density sensitive also for N e > 10 12 cm À3 , however, such densities are typical of flare plasmas, where temperature is much higher than the temperature range where Mg IX is formed, so this density dependence cannot be used for diagnostics.…”

“…The incident electron energies were chosen to encompass a wide range spanning from threshold to high energies. For transitions from within the ground configuration levels to the first 10 levels (n = 2 configurations) we calculated collision strengths at 6,12,25,50,75, 100, and 125 Ry, since the excitation energies of these transitions are lower than 5 Ry. Collision strengths for transitions between the ground configuration and the n = 3, 4, 5 configurations were calculated at 25, 50, 75, 100, and 125 Ry, since the excitation energies of these transitions are in the 11.4-20.9 Ry energy range.…”

“…The equations have been solved at electron densities of log N e (cm À3 ) = 6,7,8,9,10,11,12,13, and 14.…”

“…Vacuum spark spectra have been used by Hoory et al [8] to measure wavelengths of levels from configurations with principal quantum number n P 3, while laser plasmas have been used to measure Mg IX wavelengths for n = 2 transitions by Fawcett [9] and for X-ray satellite lines by Boiko et al [10]. Beam foil spectroscopy has been used to measure lifetimes for several Mg IX levels and transitions by Träbert and Heckmann [11], Möller et al [12] and Granzow et al [13].…”

“…The configurations used are 2s 2 , 2s2p, 2p 2 , 2l3l 0 , 2l4l 0 and 2s5l 0 , with l = s, p and l 0 = s, p, d giving rise to 92 fine-structure levels in intermediate coupling. Collision strengths are calculated at seven incident energies (6,12,25, 50, 75, 100, and 125 Ry) for the transitions within the three lowest configurations, and five incident energies (25, 50, 75, 100, and 125 Ry) for transitions between the ground configuration and the n = 3, 4, 5 configurations. Calculations have been carried out using the distorted wave approximation.…”