SOLAR-FLARE X-RAY-SPECTRA .1. WAVELENGTHS OF FE XXIV-XXV LINES IN THE REGION-LAMBDA=1.85-1.87A

Results are presented of an investigation of solar flare X-ray spectra in the region 1.70-1.95 Å, obtained aboard the 'Intercosmos-4' satellite during the maximum of solar activity (October-November, 1970). With the use of 6 high resolution spectra in the region 1.85-1.87 Å the identification of lines due to 18 transitions of 2 p → 1 s type, consisting of the resonance, intercombination and forbidden Fe xxv ion lines and the satellite Fe xxiv lines has been performed. With the use of the recent laboratory data the averaged wavelengths of the lines were obtained confirming the theoretically calculated ones with an accuracy about ± 0.0004 Å. A variable Doppler shift of the Fe xxv resonance lines was observed for the flare of November 16, 1970, which points to hot plasma motions with velocities up to 400 km s-1. © 1979 D. Reidel Publishing Co.