exist almost continuously throughout the -11-yr solar activity cycle.
The bottom-left X-ray image was taken on 7 April 2009, at activity minimum, and shows equatorial and polar coronal holes
The presence of 'anchoring' within coronal holes
and the rigid rotation of the corona is best explained by condensed matter.
are a typical feature on the sun, though they appear at different places and with more frequency at different times of the sun's activity cycle.
Such strong control of the polar fields on the solar wind distribution is considered to occur through the formation of coronal holes
over the poles.
are cooler than other parts of the Sun, and magnetic waves appear to deposit more energy in the cooler regions than in the atmosphere's warmer parts.
Japan's Hinode sun-watching satellite photographed the sun's two coronal holes
In contrast to recent minima, it displayed low sunspot numbers, a delayed new-cycle activity, weak polar magnetic fields, and smaller polar coronal holes
with less open flux.
SXI will observe solar flares, coronal mass ejections, coronal holes
and active regions in the X-ray region of the electromagnetic spectrum.
Learn about solar wind, solar flares, and coronal holes
, and practice space weather-forecasting skills.
These dark-appearing, open regions, known as coronal holes
, permit solar wind to escape into space.
The NRL researchers think that future studies of these cellular regions will lead to an improved understanding of magnetic field line reconnection at the boundaries of coronal holes
, and how these changes are transmitted outward into the solar wind.