New satellite structure of the solar and laser plasma spectra in vicinity of the Lα (Mg XII) line

Spectra in the narrow vicinity of the Mg XII resonance line at lambda=8.42 A were obtained aboard the satellites 'Intercosmos-4, -7' and the rocket 'Vertical-2', as well as from laser-produced plasma. The high resolution in solar and laboratory spectra made it possible to reveal a new spectral structure close to the Lα (Mg XII) line from both short and long wavelength sides. The main features were observed in all the spectra and were interpreted as a single or group of dielectronic satellite lines due to 2l3l''→1s3l' transitions in the He-like ions according to theoretical calculations which were carried out by means of relativistic Z-expansion technique. The derived electron temperature of the emitting volumes seemed to be approximately 3x106 K for laser plasma and about 6x106 K for the solar flares studied. The latter value is in good agreement with the temperature estimated with the help of the resonance line-to-continuum intensity ratios. (Auth.)