Observations of the solar vacuum-ultraviolet emission lines obtained by SUMER/SOHO and their interpretation in terms of atomic physics concepts are given. Electron temperature and density diagnostics of the low corona are described. Doppler line-of-sight measurements demonstrate an outflow at the base of the corona in the dark areas of coronal holes, which are seen as the source of the solar wind. Some aspects of the dynamics of the upper solar atmosphere, such as explosive events and sunspot oscillations, are mentioned as examples of the quiet-Sun activity, but spectral observations during solar flare are also shown with indications of plasmas with temperatures of several million Kelvins.
- Pub Date:
- Solar Plasma