fl128.yoshimori04 Posted: 06-Jun-93 Updated: 06-Nov-93, 7-Aug-94, 13-May-95 Events specified: Flare on 27-Oct-91 at 05:37
Collaboration: M.Yoshimori (Rikkyo University, X024862@JPNRKY00.BITNET),J.Sato, K.Suga, T.Hiraoka, K.Morimoto, K.Kawabata and K.Ohki
Scientific Questions: (a)What are elemental abundances at the site of gamma-ray production ? (b)Are these abundances different from those of the photosphere and corona ? (c)What mechanism causes the abundance variation ?
Motivation: Gamma-ray line spectra from solar flares offer a powerful new technique for studying relative elemental abundances in the solar atmosphere at the gamma-ray production site. This technique is free of many of the drawbacks associated with spectroscopic analyses at other wavelengths. Elemental abundances of the ambient gas at the site of gamma-ray production are derived from the gamma-ray line observation of the 1991 October 27 flare. The present result is compared with the abundances obtained from the gamma-ray spectroscopy of the 1891 April 27 flare and the photospheric and coronal abundances. If the abundance differences between these are found, we will solve a question on the nature of the processes responsible for these abundance variation.
Required Observations: GRS spectral and light curve data.
Update 13-May-95
We have reached the goal of our paper, so we like to close the project. The paper entitled "Solar Abundances Derived from Gamma-Ray Line Spectroscopy of the 1991 October 27 Flare (M.Yoshimori, J.Sato, K.Suga, T.Hiraoka, K.Morimoto, K.Kawabata and K.Ohki)" was published in X-Ray Solar Physics from Yohkoh, ed. Y.Uchda, T.Watanabe, K.Shibata and H.Hudson (Universal Academy Press, Inc. Tokyo, Japan), 1993, p.15.
Scientific Ourput:
Gamma-ray line spectra from solar flares offer a powerful new technique for studying relative elemental abundances in the solar atmosphere at the gamma-ray production site. This technique is free of many the drawbacks associated with spectroscopic analyses at other wavelengths. It is because nuclear deexcitation line fluences are directly proportional to the elemental abundances at the nuclear reaction site. Comparison the derived elemental abundances with those of corona, phorosphere and solar energetic particles provides important clue on a charge-dependent transport process.
Abstract:
Elemental abundances of the ambient gas at the gamma-ray production site in the solar atmosphere are derived from the gamma-ray line observation of the 1991 October 27 flare. The resultant abundances are different from the photospheric abundances. The Ne, Mg, Si and Fe abundances at the gamma-ray production site are enhanced relative to the corresponding abundances in the photosphere. However, these abundances are roughly in agreement with the coronal abundances except for Ne. The Ne abundance is enhanced by factor 2 or 3 relative to the corona.
Update 7-Aug-94
Elemental abundances of the ambient gas at the gamma-ray production site in the solar atmosphere are derived from the gamma-ray line observation of the 1991 October 27 flare (X6.1/3B). The preliminary relative abundances of C, O, Ne, Mg, Si and Fe are in agreement with those of the 1981 April 27 flare observed with SMM. Our preliminary paper entitled "Solar Abundances Derived from Gamma-ray Line Spectroscopy of the 1991 October 27 Flare by M.Yoshimori, J.Sato, K.Suga, T.Hiraoka, K.Morimoto, K.Kawabata and K.Ohki" was published in X-Ray Solar Physics from Yohkoh, ed. Y.Uchida, T.Watanabe, K.Shibata and H.S.Hudson (Universal Academy Press, Inc. Tokyo, Japan), 1993, p.15.
Recently we have developed the revised response matrix of the gamma-ray spectrometer. We are calculating the detailed elemental abundances using both the revised response matrix and the gamma-ray production yield. We compare the revised result with the photospheric and coronal abundances.
Update 06-Nov-93
Elemental abundances of the ambient gas at the gamma-ray production site in the solar atmosphere are derived from the ganmma-ray line observbation of the 1991 October 27 flare (X6.1/3B) The resultant relative abundances of C, O, Ne, Mg, Si and Fe are in agreemnt with those from the SMM gamma-ray observation of the 1981 April 27 flare within the experimental errors. The present abundances are different from the photospheric abundances. In particular, the Ne, Mg, Si and Fe abundances at the gamma-ray production site are enhanced relative to the corresponding photospheric abundances. The present abundances resemble the coronal abundances except for Ne. The Ne abundance at the gamma-ray production site is enhanced by factor 2 or 3 relative to the corona.
The paper entitled
Solar Abundances Derived from Gamma-Ray Line Spectroscopy of
the 1991 October 27 Flare
by M.Yoshimori, J.Sato, K.Suga, T.Hiraoka, K.Morimoto,
K.Kawabata and K.Ohki
will appear in the proceedings of the February 93 Yohkoh Science
Meeting.