Fe XVII X-Ray Lines in Solar Coronal Plasmas
Abstract
Calculated intensities of the Fe XVII X-ray lines in the 15 - 17 Å wavelength range are compared with measured line intensities in solar spectra. The intensity ratio of the Fe XVII 16.776 Å line to any one of several nearby Fe XVIII 2p5-2p43s transitions is suitable for determining temperature. Using this ratio, and comparing theory and observed solar spectra, excellent agreement is found for all the major Fe XVII and Fe XVIII features in this region, apart from the Fe XVII 15.015 Å line, which is resonance scattered in solar active region and flare spectra. The observed flux of this line is less than the theoretical value by a factor R2 which varies between 0.2 and 0.9. The relation of R2 to the heliographic position and shape of the emitting feature is examined.
- Publication:
-
Astronomical Society of the Pacific Conference Series
- Pub Date:
- 1996
- Bibcode:
- 1996ASPC..111..125G
- Keywords:
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- Solar X Rays: Iron Lines;
- Solar X Rays: Solar Corona