Nonthermal Velocities in Solar Active Regions Observed with the Extreme-Ultraviolet Imaging Spectrometer on Hinode
Abstract
We discuss nonthermal velocities in an active region as revealed by the Extreme-Ultraviolet Imaging Spectrometer (EIS) on the Hinode spacecraft. The velocities are derived from spectral line profiles in the extreme-ultraviolet (EUV) from a strong line of Fe XII at 195.12 Å by fitting each line profile to a Gaussian function. We compare maps of the full width at half-maximum values, the Fe XII spectral line intensity, the Fe XII Doppler shift, the electron temperature, and electron density. We find that the largest widths in the active region do not occur in the most intense regions, but seem to concentrate in less intense regions, some of which are directly adjacent to coronal loops, and some of which concentrate in regions which also exhibit relative Doppler outflows. The increased widths can also occur over extended parts of the active region.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- September 2007
- DOI:
- 10.1086/522087
- Bibcode:
- 2007ApJ...667L.109D
- Keywords:
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- Sun: Atmospheric Motions;
- Sun: Corona;
- Sun: UV Radiation