Solar cycle variation of the temperature structure within the cores of coronal streamers
Abstract
We use the Coronal Diagnostic Spectrometer onboard the Solar and Heliospheric Observatory (SOHO) to analyze conditions in coronal streamer structures observed close to solar minimum (1996, July 8) and near maximum (1999, August 5). From emission line intensities (Fe IX-XV ions), the line ratio method gives the radial temperature behaviour. The solar minimum peak values were about 1.4 MK at 1.3 R0, while near solar maximum values were consistent with Yohkoh observations at the last maximum, displaying an asymptotic temperature of around 2.2 MK above 1.2 R0. We discuss the observations in relation to possible mechanisms for energy deposition in large coronal structures.
- Publication:
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From Solar Min to Max: Half a Solar Cycle with SOHO
- Pub Date:
- June 2002
- Bibcode:
- 2002ESASP.508..371C
- Keywords:
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- Sun: Corona;
- Sun: Activity;
- Sun: X-Rays