J. Phys. Colloques
Volume 49, Numéro C1, Mars 1988IAU Colloquium N° 102 on UV and X-ray Spectroscopy of Astrophysical and Laboratory Plasmas
|Page(s)||C1-189 - C1-193|
J. Phys. Colloques 49 (1988) C1-189-C1-193
TIME VARIATIONS OF THE CALCIUM ELEMENTAL ABUNDANCE IN FLARES FROM NOAA ACTIVE REGIONS 2562 AND 2779J. SYLWESTER1, M.-C. ZOLCINSKI-COUET2, R.D. BENTLEY2 et J.R. LEMEN3
1 Space Research Centre, Polish Academy of Sciences, Kopernika 11, PL-51-622 Wroclaw, Poland
2 Mullard Space Science Laboratory, Holmbury St Mary, GB-Dorking, RH5 6NT, Surrey, Great-Britain
3 Lockheed Palo Alto Research Laboratory, Dept. 91-20, Building 255, 3251 Hanover Street, Palo Alto, CA 94304, U.S.A.
Analysis of flare spectra obtained with the Bent Crystal Spectrometer aboard the Solar Maximum Mission (SMM) satellite enables the determination of the fluxes in the resonance (w) line of Ca XIX and the near-by continuum. The line-to-continuum intensity ratio is a sensitive measure of the calcium elemental abundance (ACa) relative to hydrogen in the emitting plasma. In previous investigations we found the calcium abundance varies from flare to flare. In the present investigation we analyse the variations of ACa for flares which occurred in two active regions well observed by SMM. We conclude that it is not possible to correlate the abundance variations with the time of the flare occurrence as suggested in an earlier paper for flares produced from a single active region. Further, we find no convincing correlation of abundance variation with any other flare characteristics. This negative result will stimulate future work on the physical interpretation of the calcium abundance variation.