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.
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Due to the rotation of the Sun, one of its coronal holes has been oriented toward the direction of Earth.
Solar Storm From Hole On Sun's Surface To Hit Earth
Coronal holes exist almost continuously throughout the -11-yr solar activity cycle.
UNDERSTANDING SPACE WEATHER: Part III: The Sun's Domain: The solar wind is a continuous, varying outflow of high-temperature plasma, traveling at hundreds of kilometers per second and stretching to over 100 au from the Sun
The bottom-left X-ray image was taken on 7 April 2009, at activity minimum, and shows equatorial and polar coronal holes.
Heating mechanisms of the solar corona
[35] used the full-disk He ii 304 [Angstrom] movies from the Atmospheric Imaging Assembly on SDO to study the cool (T ~ [10.sup.5] K) component of X-ray jets observed in polar coronal holes by XRT.
Modeling Kelvin-Helmholtz Instability in Soft X-Ray Solar Jets
However, at coronal holes, the magnetic field lines don't close back on themselves and blow straight out into space.
A Gigantic Hole In The Sun
The presence of 'anchoring' within coronal holes and the rigid rotation of the corona is best explained by condensed matter.
Forty lines of evidence for condensed matter--the sun on trial: liquid metallic hydrogen as a solar building block
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.
Gigantic coronal hole spotted over Sun's north pole
It is clearly shown here that the fast wind at high latitudes is closely associated with polar coronal holes where the magnetic field is open, and also that the slow wind at the equator is mostly linked to either the boundary region of polar coronal holes or the isolated low-latitude coronal holes.
Three-dimensional exploration of the solar wind using observations of interplanetary scintillation
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.
Solar science / waves might heat sun's atmosphere
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.
SOHO-23; understanding a peculiar solar minimum; proceedings
SXI also will monitor coronal holes -- persistent sources of high-speed solar wind.
LOCKHEED MARTIN SXI LAUNCHED ON NOAA SPACECRAFT
Learn about solar wind, solar flares, and coronal holes, and practice space weather-forecasting skills.
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