43 research outputs found
Response of the solar atmosphere to magnetic field evolution in a coronal hole region
Methods. We study an equatorial CH observed simultaneously by HINODE and
STEREO on July 27, 2007. The HINODE/SP maps are adopted to derive the physical
parameters of the photosphere and to research the magnetic field evolution and
distribution. The G band and Ca II H images with high tempo-spatial resolution
from HINODE/BFI and the multi-wavelength data from STEREO/EUVI are utilized to
study the corresponding atmospheric response of different overlying layers.
Results. We explore an emerging dipole locating at the CH boundary. Mini-scale
arch filaments (AFs) accompanying the emerging dipole were observed with the Ca
II H line. During the separation of the dipolar footpoints, three AFs appeared
and expanded in turn. The first AF divided into two segments in its late stage,
while the second and third AFs erupted in their late stages. The lifetimes of
these three AFs are 4, 6, 10 minutes, and the two intervals between the three
divisions or eruptions are 18 and 12 minutes, respectively. We display an
example of mixed-polarity flux emergence of IN fields within the CH and present
the corresponding chromospheric response. With the increase of the integrated
magnetic flux, the brightness of the Ca II H images exhibits an increasing
trend. We also study magnetic flux cancellations of NT fields locating at the
CH boundary and present the obvious chromospheric and coronal response. We
notice that the brighter regions seen in the 171 A images are relevant to the
interacting magnetic elements. By examining the magnetic NT and IN elements and
the response of different atmospheric layers, we obtain good positive linear
correlations between the NT magnetic flux densities and the brightness of both
G band (correlation coefficient 0.85) and Ca II H (correlation coefficient
0.58).Comment: 9 pages, 9 figures. A&A, in pres