Flare June 7, 2011, and Analysis of Eruptive Prominence Fragments

Abstract

Solar flares can be accompanied by high plasma velocities exceeding several hundred km/s. Detection and measurement of such velocities is limited by narrow-band and small wavelength range in most solar instruments. However, similar events with Doppler velocities exceeding two hundred km/s have been detected by the solar optical spectrographs at the Ondřejov Observatory. The results of the analysis of our multi-wavelength observation performed during the solar flare of June 7, 2011 and the calculation of several physical parameters of the coronal mass ejection fragments following the flare have been present. The calculation of the radiation of heated gas have been performed with allowance for self-absorption in the spectral lines of hydrogen and calcium. All the crucial processes of discrete level populating and depopulating have been taken into account in the balance equations. The theoretical radiation fluxes in the lines have coincided with those observed in the temperature range of 6300–10000 K at a gas concentration of  ~\((3{\kern 1pt} - {\kern 1pt} 5) \times {{10}^{{10}}} {\text{c}}{{{\text{m}}}^{{ - 3}}}\), a gas layer thickness of \(6800{\kern 1pt} - {\kern 1pt} 7000\) km, and a linear concentration of \((2{\kern 1pt} - {\kern 1pt} 4) \times {{10}^{{19}}} {\text{c}}{{{\text{m}}}^{{ - 3}}}\).