O VI (λ = 1032 Å) profiles in and above an active region prominence, compared to quiet Sun center and limb profiles
✍ Scribed by J. C. Vial; P. Lemaire; G. Artzner; P. Gouttebroze
- Book ID
- 104645133
- Publisher
- Springer
- Year
- 1980
- Tongue
- English
- Weight
- 1023 KB
- Volume
- 68
- Category
- Article
- ISSN
- 0038-0938
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✦ Synopsis
O vx (A = 1032 A) profiles have been measured in and above a filament at the limb, previously analyzed in HrI, Mg n, Ca n resonance lines (Vial etal., 1979). They are compared to profiles measured at the quiet Sun center and at the quiet Sun limb.
Absolute intensities are found to be about 1.55 times larger than above the quiet limb at the same height (3"); at the top of the prominence (15" above the limb) one finds a maximum blue shift and a minimum line width. The inferred non-thermal velocity (29 km s -1) is about the same as in cooler lines while the approaching line-of-sight velocity (8 km s -1) is lower than in Ca II lines.
The O vI profile recorded 30" above the limb outside the filament is wider (FWHM = 0.33 A). It can be interpreted as a coronal emission of O vl ions with a temperature of about 106 K, "and a non-thermal velocity (NTV) of 49 km s -1. This NTV is twice the NTV of quiet Sun center OvI profiles. Lower NTV require higher temperatures and densities (as suggested by K-coronameter measurements). Computed emission measures for this high temperature regime agree with determinations from disk intensities of EUV lines.