Electron Densities in Active Region Loops Observed with Hinode/EIS
Abstract
Active region observations with the Transition Region and Coronal Explorer (TRACE) showed that loops near 1 MK appear to have high densities relative to the predictions of scaling laws based on steady heating. These loops also persist much longer than a radiative cooling time. This lead to the formation of models based on the impulsive heating of small scale filaments. With the launch of the EUV Imaging Spectrometer (EIS) on Hinode we now have a much more detailed view of coronal loops at these temperatures. We find that the temperatures, densities, and filling factors inferred from the new spectroscopic data are largely consistent with our interpretation of the earlier TRACE observations. The impulsive heating models also predict low densities relative to the steady heating models at high temperatures, and we will discuss the EIS evidence for hot, underdense loops in solar active regions.
- Publication:
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AGU Spring Meeting Abstracts
- Pub Date:
- May 2008
- Bibcode:
- 2008AGUSMSP41C..02W
- Keywords:
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- 7509 Corona;
- 7519 Flares