Characterizing the Background Corona with SDO/AIA

Abstract:

Characterizing the nature of the solar coronal background would enable
scientists to more accurately determine plasma parameters, and may lead to a
better understanding of the coronal heating problem. Because scientists study
the 3D structure of the Sun in 2D, any line of sight includes both foreground and
background material, and thus, the issue of background subtraction arises. By
investigating the intensity values in and around an active region, using multiple
wavelengths collected from the Atmospheric Imaging Assembly (AIA) on the
Solar Dynamics Observatory (SDO) over an eight-hour period, this project aims
to characterize the background as smooth or structured. Different methods were
employed to measure the true coronal background and create minimum
intensity images. These were then investigated for the presence of structure.
The background images created were found to contain long-lived structures,
including coronal loops, that were still present in all of the wavelengths, 131,
171, 193, 211, and 335 Å. The intensity profiles across the active region
indicate that the background is much more structured than previously thought.