Intensities and profiles of XUV transition zone lines in a quiet sun region compared to a polar coronal hole
Journal Article
·
· Astrophys. J., Lett., v. 202, no. 3, pp. L147-L150
The intensities of XUV transition zone lines from limb spectra of a quiet sun region and a polar coronal hole are compared. The spectra were obtained from the NRL slit spectrograph on Skylab, and cover a region from -12'' within the limb (1''approx. =725 km) to +20'' above the limb. The lines selected for comparison are formed at temperature that range from 3.6x10$sup 4$ to 2.2x10$sup 5$ K. Lines of the higher temperature ions, e.g., O v, are significantly less intense in the coronal hole, and lines of lower-temperature ions show little change. Profiles of selected optically thin transition zone lines from the quiet Sun and coronal hole spectra are also shown. The lines are broader than expected in ionization equilibrium, and bulk motion velocities are deduced from the widths of the lines. There appears to be little, if any, statistically significant difference in the velocities obtained from the quiet Sun and the coronal hole. (AIP)
- Research Organization:
- E. O. Hulburt Center for Space Research, Naval Research Lab., Washington, DC
- Sponsoring Organization:
- USDOE
- NSA Number:
- NSA-33-024090
- OSTI ID:
- 4057339
- Journal Information:
- Astrophys. J., Lett., v. 202, no. 3, pp. L147-L150, Journal Name: Astrophys. J., Lett., v. 202, no. 3, pp. L147-L150; ISSN AJLEA
- Country of Publication:
- United States
- Language:
- English
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