The Evolution of Photospheric Magnetic Fields Inside and Around the Coronal Holes
Abstract
We investigated the evolution of photospheric magnetic fields around the boundaries of 22 coronal holes with a variety of sizes and complexities from August 21 2003 to December 30 2006. The boundary of each coronal hole was defined from the 195Å. images obtained by SOHO Extreme ultraviolet Imaging Telescope (EIT). The SOHO Michelson Doppler Imager (MDI) full disk data were employed to study the magnetic element evolution. The coronal hole area was divided into three parts (inside, outside and the boundary of the coronal hole), via image process techniques. The movies of each part of the 22 coronal holes were made. The positive and negative magnetic elements were calculated in each of the three parts respectively. We present the results on the rates of flux emergence cancellations and flow patterns in these 3 parts.
- Publication:
-
American Astronomical Society Meeting Abstracts #210
- Pub Date:
- May 2007
- Bibcode:
- 2007AAS...210.9126T