fl146.kato04 Posted: 25-Oct-93 Updated: 31-May-94, 18-Feb-95, 30-Sep-95, 07-Jul-96 Events specified: 6-Sep-92 flare
T. Kato and T. Fujiwara* , BCS Group
National Institute for Fusion Science, Nagoya, 464-01,Japan (NIFS, Fax : 052-789-1037) *Dep. of Education, Aichi University of Education, Kariya, 448, Japan
We have studied time evolution of BCS spectra of He like S XV, Ca XIX and Fe XXV ions observed by the Yohkoh satellite from flares on 6th September 1992( 05:05 and 08:59). Apparent ion temperatures are derived from the line width of S XV and Ca XIX spectra. Electron temperatures for S XV, Ca XIX and Fe XXV ions are derived through synthetic spectra mainly from the intensity ratios of the satellite lines to the resonance line. The time evolution of the emission measure of the blue shifted component is obtained. The emission measures derived from the BCS spectra will be discussed for the comparison with SXT, HXT and radio data. The ion ratios derived from the ratios of line intensities will be studied relating to the ionization equilibrium.
Update 07-Jul-96
We have made a paper on this subject. It was published in Institute report as NIFS -396(1996) and submitted in Astrophy. Journal. Abstrac is as follows,
X-ray spectral analysis of Yohkoh BCS data on Sep. 6 1992 flares
Takako KATO and Tomoko FUJIWARA* and Yoichiro HANAOKA**
National Institute for Fusion Science, Nagoya, 464-01,Japan *Dep. of Education, Aichi University of Education, Kariya, 448, Japan **Nobeyama Radio Observatory, National Astronomical Observatory, Nobeyama, Nagano 384-13, Japan
We have studied the time evolution of BCS spectra of He - like S XV, Ca XIX and Fe XXV ions observed by the Yohkoh satellite for solar flares on 6th September 1992 at 05:05 (M2.4 class) and 08:59(M3.3 class). Electron temperatures are derived through the fit of the synthetic spectra to the observed ones. Apparent ion temperatures are derived from the line width of S XV and Ca XIX spectra. The blue shifted component in the rising phase is separated from the main component of the Ca XIX spectra. The emission measures are derived from the spectra without assuming ionization equilibrium and solar abundances for the first time. The time variation of these parameters are compared with hard X-rays, soft X-rays and radio measurements. In the preheating phase, the moderate increase of thermal plasma with turbulence indicated from the line width is observed. The time evolution of the blue shift component coincides with that of the burst in hard X-rays and microwaves which are produced by non - thermal high energy electrons. The ion density ratios derived from the spectra show a time - dependent non equilibrium ionization. They are shifted from the equilibrium values indicating an ionizing plasma.
Update 30-Sep-95
We have studied the time evolution of BCS spectra of He - like S XV, Ca XIX and Fe XXV ions observed by the Yohkoh satellite for solar flares on 6th September 1992 at 05:05 (M2.4 class) and 08:59(M3.3 class). Electron temperatures are derived through the fit of the synthetic spectra to the observed ones. Apparent ion temperatures are derived from the line width of S XV and Ca XIX spectra. The blue shifted component in the rising phase is separated from the main component of the Ca XIX spectra. The emission measures are derived from the spectra without assuming ionization equilibrium and solar abundances for the first time. The time variation of these parameters are compared with HXT, SXT and radio measurements. The ion density ratios derived from the ratios of line intensities of Fe ions show a time - dependent non equilibrium ionization. They are shifted from the equilibrium values indicating an ionizing plasma.
We are writing a paper now.
Update 18-Feb-95
We are analysing BCS spectra of S XV, Ca XIX and Fe XXV ions observed by Yohkoh satellite, for two flares on 6th September 1992 at 05:05UT(M2.4class) and 08:59UT(M3.3class). Comparing the synthetic spectra including line and continuum emission to the observed spectra, we have obtained the electron temperature from the line intensity ratios, ion temperature from the line broadening, volume emission measure and ion abundance from the intensity ratio of resonance line to the continuum emission. The blue-shifted components with broad line width of Ca XIX spectra appear from the initial phase to the rising phase. At the same time the main component of the resonance line shows also the large line broadening. These phenomena indicate the evaporation and the turbulence in the rising phase of the solar flare. The emission of HXT(M1,M2 Band) increase rapidly and the polarization degree observed by Nobeyama-radio heliograph decrease during the rising phase. The abundance of Ca and Fe obtained from the line to continuum ratio show the larger value than the solar abundance after the rising phase. The time variation of the ion abundance indicates the non equilibrium ionization.
Update 31-May-94
We are analysing BCS spectra on 6th September 1992. We have found a high temperature plasma near 1 keV from the Ca XIX spectra in the inital phase of flares before the rizing phase. During the rising phase, the blue shifted component of a relative velocity 200 km/s is observed. We have derived the electron temperature, emission measures from Fe XXV, Ca XIX and S XV spectra, respectively as a function of time as well as the ion abundances of Fe ions. We will compare the results with using the different atomic data.