Spectroscopic features in the EUV emission of a M8 flare observed by SUMER
Abstract
On May 9, 1999 a flare of size M8 occurred while SUMER obtained a spectral scan above the active region NOAA 8537 at the west limb. We recorded spectra during the pre-flare phase, at flare onset, and during the decay phase. More than 60 flare lines were observed during this event, which include Fe XVIII - Fe XXIII lines that provide evidence of 107 K plasmas. We also recorded lines from He-like ions, such as Ne IX, Na X, Mg XI or Si XIII. Accurate wavelength measurements of such lines are of interest in basic atomic physics studies. Using plasma diagnostic techniques, we investigated the temporal evolution of the electron densities and temperatures during the event. Since the spectra contain lines from many different elements, we were able to determine elemental abundances in the flaring plasma.
- Publication:
-
Recent Insights into the Physics of the Sun and Heliosphere: Highlights from SOHO and Other Space Missions
- Pub Date:
- 2001
- Bibcode:
- 2001IAUS..203..260C