Gamma‐ray line measurements and ambient solar abundances
作者:
Gerald H. Share,
Ronald J. Murphy,
Jeffrey G. Skibo,
期刊:
AIP Conference Proceedings
(AIP Available online 1996)
卷期:
Volume 374,
issue 1
页码: 162-171
ISSN:0094-243X
年代: 1996
DOI:10.1063/1.50952
出版商: AIP
数据来源: AIP
摘要:
We review measurements of ten narrow &ggr;‐ray lines in 19 X‐class solar flares observed by the Solar Maximum Mission spectrometer from 1980 to 1989 (1) which showed that abundances of elements in the flare plasma are grouped with respect to their first ionization potentials (FIP), indicated that both the Ne/O and C/O line ratios are dependent on the spectral index of accelerated particles, and suggested that the range in low‐FIP/high‐FIP line ratios is similar to that in comparing coronal and photospheric compositions. We confirm this range in variability using the (Mg+Si+Fe)/Ne line ratio, which is not strongly dependent on the spectrum of accelerated ions. We also use measurements of the positronium continuum and annihilation line to show that &ggr;‐rays from flares with the lowest low‐FIP to high‐FIP ratios were produced deep in the chromosphere where the abundances should be close to photospheric. ©1996 American Institute of Physics.
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