Solar atmospheric abundances from gamma ray spectroscopy
作者:
Reuven Ramaty,
Natalie Mandzhavidze,
Benzion Kozlovsky,
期刊:
AIP Conference Proceedings
(AIP Available online 1996)
卷期:
Volume 374,
issue 1
页码: 172-183
ISSN:0094-243X
年代: 1996
DOI:10.1063/1.50953
出版商: AIP
数据来源: AIP
摘要:
We used SMM gamma ray data from 19 solar flares to study ambient elemental abundances in the solar atmosphere. We found that the abundance ratios of low FIP (first ionization potential) to high FIP elements (Mg/O, Si/O, Fe/O) are enhanced relative to photospheric abundances and may vary around their respective coronal values. For the high FIP elements (C, O, Ne) we showed that: (i) The gamma ray data allows a good determination of the C to O abundance ratio; the data are consistent with a C/O which does not vary from flare to flare; and the best fit value is C/O=0.4. (ii) The derived value of Ne/O (∼0.25) is higher than the coronal value of 0.15 obtained from solar energetic particle data and some EUV and X‐ray observations of photospheric material. To avoid Ne/O higher than 0.3 a steep accelerated particle energy spectrum extending down to about 1 MeV/nucl is needed. This implies that a large fraction of the available flare energy is contained in accelerated ions. ©1996 American Institute of Physics.
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