coronal holes


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coronal holes

Regions of exceptionally low density and temperature compared with the surrounding solar or stellar corona. They overlie areas of the Sun's disk that are characterized by relatively weak divergent (and therefore primarily unipolar) magnetic fields, and are thought to be the primary source of the high-speed streams of energetic charged particles in the solar wind.
References in periodicals archive ?
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.
Coronal holes 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.
Coronal holes 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 on Feb.
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.