Abstract
The Coronal Diagnostic Spectrometer (CDS) on SOHO is a grazing/normal incidence spectrograph, aimed to produce stigmatic spectra of selected regions of the solar surface in six spectral windows of the extreme ultraviolet from 150 Å to 785 Å (Harrison et al. 1995). In the present work, CDS, EIT, MDI and Yohkoh observations of active region lops have been analyzed. These observations are part of JOP 54. CDS monochromatic images from lines at different temperatures have been co-aligned with EIT and MDI images, and loop structures have been clearly identified using Fe XVI emission lines. Density sensitive lines and lines from adjacent stages of ionization of Fe ions have been used to measure electron density and temperature along the loop length; these measurements have been used to determine the electron pressure along the loop and test the constant pressure assumption commonly used in loop modeling. The observations have been compared with a static, isobaric loop model (Landini and Monsignori Fossi 1975) assuming a temperature-constant heating function in the energy balance equation. Good agreement is found for the temperature distribution along the loop at the coronal level. The model pressure is somewhat higher than obtained from density sensitive line ratios.
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References
Harrison, R. A., et al.: 1995, Solar Physics, 162, 233.
Landi, E., Landini, M., Dere, K. P., Young, P. R., and Mason, H. E.: 1999, A&A, in press.
Landini, M., and Monsignori Fossi, B. C.: 1975, A&A, 42, 213.
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© 1999 Springer Science+Business Media Dordrecht
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Landini, M., Brković, A., Landi, E., Rüedi, I., Solanki, S. (1999). Loop Models from SOHO Observations. In: Kohl, J.L., Cranmer, S.R. (eds) Coronal Holes and Solar Wind Acceleration. Springer, Dordrecht. https://doi.org/10.1007/978-94-015-9167-6_37
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DOI: https://doi.org/10.1007/978-94-015-9167-6_37
Publisher Name: Springer, Dordrecht
Print ISBN: 978-90-481-5267-4
Online ISBN: 978-94-015-9167-6
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