Limb brightening of XUV lines of the ions Cm Nm, Niv, Ore, Oiv, Ov and Silv is compared with that predicted by a modified version of a coronal model developed by Dupree and Goldberg. Systematic differences between the predicted and observed limb brightening are found. These differences can be elimin
Microwave solar limb brightening
โ Scribed by I. A. Ahmad; M. R. Kundu
- Publisher
- Springer
- Year
- 1981
- Tongue
- English
- Weight
- 674 KB
- Volume
- 69
- Category
- Article
- ISSN
- 0038-0938
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โฆ Synopsis
Previous models of microwave limb brightening have omitted the alignment of spicules along supergranule boundaries, have neglected the high temperature sheath around spicules, and have assumed an interspicular medium which was averaged over chromospheric network and non-network regions. We present a model which includes these factors. By constraining the model to conform to results from earlier UV and optical studies we are effectively left with two free parameters: the temperature at the core of the spicules, Tc .... and (at solar minimum), the interspicular chromospheric network density model of the lower transition zone. The absence of limb brightening at the short millimeter wavelengths implies Tcor~ ~< 6000 k. Differences between the model and certain deconvolved observations near 9 mm are expected as a consequence of an extension of emission beyond the optical limb, predicted by the model, which affects the accuracy of the deconvolution technique. Unlike models which assume homogeneous spicules in a random distribution, ours does not require an abnormally high spicule area.
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OSO-IV observations of the equatorial limb brightening of XUV resonance lines of Nv, O w, Ne vii, Mg x and Si xii are interpreted with a modified version of a coronal model developed by Dupree and Goldberg (1967). Good agreement is obtained between the observed limb brightening and that predicted by
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