Using Hinode EUV Imaging Spectrometer (EIS) spectra recorded daily at Sun center from the end of 2006 to early 2011, we studied the long-term evolution of the quiet corona. The light curves of the higher temperature emission lines exhibit larger variations in sync with the solar activity cycle while the cooler lines show reduced modulation. Our study shows that the high temperature component of the corona changes in quiet regions, even though the coronal electron density remains almost constant there. The results suggest that heat input to the quiet corona varies with the solar activity cycle.
- Pub Date:
- August 2012
- Solar cycle;
- Spectral line;
- intensity and diagnostics;
- Astrophysics - Solar and Stellar Astrophysics
- 9 pages, 5 figures, Accepted for publication in Solar Physics