Chromospheric and Transition region He lines during a flare
Abstract
An observing campaign (SOHO JOP 139), coordinated between ground based and SOHO instruments, has been planned to obtain simultaneous spectroheliograms of the same area in several spectral lines. The chromospheric lines Ca II K, Hα and Na I D as well as He I 10830, 5876, 584 and 304 Ålines have been observed. These observations allow us to build semi-empirical models of the atmosphere before and during a small flare. With these models, constructed to match the observed line profiles, we can test the He abundance value.
- Publication:
-
Memorie della Societa Astronomica Italiana
- Pub Date:
- 2003
- Bibcode:
- 2003MmSAI..74..639F
- Keywords:
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- Solar activity;
- Flares;
- Helium