Coronal holes are areas where the Sun's corona is darker, colder, and has lower-density plasma than average.
Coronal Holes
Coronal holes are regions where the corona is dark. These features were discovered when X-ray telescopes were first flown above the earth's atmosphere to reveal the structure of the corona across the solar disc.
Coronal Hole is an area of the corona which appears dark in X-rays and ultraviolet light. The holes usually are located at the poles of the Sun, but can occur at other places.
Coronal Hole. An extended region of the corona, exceptionally low in density (large open "gaps"), and associated with photospheric regions.
Coronal Holes These are regions where the corona is dark. They are often found at the Sun's poles, and are associated with open magnetic field lines. Most of the solar wind originates from these holes in the corona.
coronal hole Vast regions of the Sun's atmosphere where the density of matter is about 10 times lower than average. The gas there streams freely into space at high speeds, escaping the Sun completely.
Coronal Hole
An Area of the solar surface that is dark at X-ray wavelengths; thought to be associated with divergent magnetic fields and the source of the solar wind.
Cosmic Ray ...
Coronal Hole - A low density, dim region in the Sun's corona. Coronal holes occur in regions of open magnetic field lines where gases can flow freely away from the Sun to form the solar wind ...
Coronal hole--an area in the Sun's corona that appears dark when viewed in the far UV or in the long-wavelength end of the x-ray range.
Coronal Hole
An area where the extreme-ultraviolet and X-ray coronal emission is abnormally low or absent; a coronal region apparently associated with diverging magnetic fields.
Coronal Hole
Regions in the corona from which the high-speed solar wind is known to originate. Coronal holes, usually found near the Sun's poles, are large regions in the corona that are less dense and cooler than the surrounding region.
Flare ...
Coronal holes Large regions in the corona that are less dense and cooler than surrounding areas. There is a constant flow of low density plasma escaping from the holes.
More about coronal holes...
Coronal holes are areas in the coronal where the magnetic field loops out into space instead of looping back into the Sun, areas of magnetic anomalies (they often occur at the poles). In X-ray photographs of the Sun, coronal holes are black areas.
CORONAL HOLES
Coronal holes are areas in the coronal where the Sun's magnetic field loops out into space instead of looping back into the Sun, areas of magnetic anomalies (they often occur at the poles).
polar plume (SOHO Glossary - GSFC) Bright structure of out-flowing gas which occur along magnetic field lines in coronal holes. These field lines extend into the solar system.
These loops are the closed-magnetic flux cousins of the open-magnetic flux that can be found in coronal hole (polar) regions and the solar wind. Loops of magnetic flux well up from the solar body and fill with hot solar plasma.
This ominous, dark shape sprawling across the face of the Sun is a coronal hole -- a low density region extending above the surface where the solar magnetic field opens freely into interplanetary space.
The Sun's coronal holes were discovered thanks to these efforts. Many of the experiments conducted investigated the astronauts' adaptation to extended periods of microgravity.
The constant flow of material pushing out from the corona is called the solar wind, and it tends to come from regions called coronal holes. The gas there is cooler and less dense than the rest of the corona, resulting in less radiation.
During the period that Genesis collected matter, the Sun was at a high level of activity and relatively small coronal holes occured at different solar latitudes.
Where the magnetic field is open, the hot material escapes, and a coronal hole results.
The team focused on Coronal Interaction Regions (CIRs), high pulses of solar wind that arise when fast moving solar wind particles spewing out of a coronal hole catch a slower flow ahead and the plasma becomes compressed.
During periods of quiet, the corona is more or less confined to the equatorial regions, with "coronal holes" covering the polar regions.
GLOSSARY What is dark matter? How long is a light-year? Have you ridden a galactic plane? Can you fill in a coronal hole? Look up these and other astronomical terms.
ADDITIONAL RESOURCES external links ...
At a temperature of several million degrees, the corona is hotter than the surface of the Sun, and glows at X-ray wavelengths. The often irregularly-shaped X-ray images can trace coronal holes and coronal mass ejections, ...
Most of the corona is trapped close to Sun by loops of magnetic field lines. In X-rays, those regions appear bright. Some magnetic field lines do not loop back to the Sun and will appear dark in X-rays. These places are called ``coronal holes''.
The solar wind emanates radially from all parts of the Sun: the fast wind originates from the coronal holes and the quiet Sun, whereas the slow wind arises from the coronal streamers.
An emission line of Fe XIV at 5303 Å - the strongest line in the Solar corona. [H76]
Coronal Hole ...
 See also: Corona, Solar, Sun, Solar wind, Field
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