
	Where results make sense

Topic: Coronal Holes

Related Topics

Hole band

supermassive black hole

electron hole

ozone hole

Woods Hole Oceanographic Institution

Jackson Hole

primordial black holes

Big Hole River

Timeline of black hole physics

Jackson Hole, Wyoming

spider hole

In the News (Wed 23 Dec 09)

Northern Trust

Marvin Harrison

Peter Chernin

Gary Locke

Match Play

Penelope Cruz

Mickey Rourke

AR Rahman

Danny Boyle

Hugh Jackman

	coronal hole
		Coronal holes are of very low density (typically 100 times lower than the rest of the corona) and have an open magnetic field structure; in other words, magnetic field lines emerging from the holes extend indefinitely into space rather than looping back into the photosphere.
		This open structure allows charged particles to escape from the Sun and results in coronal holes being the primary source of the solar wind and the exclusive source of its high-speed component.
		During the minimum years of the solar cycle, coronal holes are confined to the Sun’s polar regions, while at solar maximum they can open up at any latitudes.
	www.daviddarling.info /encyclopedia/C/coronal_hole.html (211 words)

	STR Theory Science
		Coronal holes are low density regions where the solar magnetic field is open to interplanetary space, thus providing the Sun's magnetic connection to the heliosphere.
		Coronal holes seem to rotate rigidly and are somehow impervious to differential rotation, even though the underlying photospheric field is clearly being sheared by the rotation.
		As shown in Figure 3, the coronal hole boundary now passes south of the negative polarity spot, and the topology of the streamer surface is strongly distorted to match that of the fan.
	solartheory.nrl.navy.mil /solartheory/hole.html (1009 words)

	[Forum] Tom: Coronal hole streams & Aurora
		For me the year 2003 was especially the year the strong coronal hole streams, when repeatedly coronal holes produced at least 1 evening of strong aurora and up to 4 little less good aurora nights in a row after that.
		Coronal hole effects at the Earth (during the peak of coronal hole effects) vary from cycle to cycle.
		During the rising and maximum phase of the cycle, geomagnetic and auroral activity is dominated by the impact of coronal mass ejections.
	www.spacew.com /pipermail/forum/2004-October/001016.html (969 words)

	Corona - Wikipedia, the free encyclopedia
		During periods of quiet, the corona is more or less confined to the equatorial regions, with "coronal holes" covering the polar regions.
		These are enormous loops of coronal material traveling outward from the Sun at over a million kilometres per hour, containing roughly 10 times the energy of the solar flare or prominence that triggered them.
		The coronal heating problem in astronomy and astrophysics relates to the question of why the temperature of the Sun's corona is millions of kelvins higher than that of the surface.
	en.wikipedia.org /wiki/Corona (1335 words)

	SOHO CDS/GIS
		Observations of oscillations in coronal loops are sought in order to determine the prescence of waves in the corona and to investiagte a possible source of coronal heating.
		Coronal holes have long been known to be the source region of the fast solar wind.
		Observations of coronal holes were difficult are difficult due to the very low intensities and SOHO provided the first opportunity to make such measurements with the required accuracy.
	www.mssl.ucl.ac.uk /www_solar/gis/gis_science_high.html (649 words)

	Extrapolation of the photospheric magnetic field into the corona and inner heliosphere using the three-layer model (Site not responding. Last check: 2007-11-01)
		Magnetic field structures in the corona, such as open field regions (coronal holes) and the neutral line (the base of the heliospheric current sheet, HCS) are obtained by extrapolation of the observed photospheric magnetic field into the corona.
		Coronal helmet streamers observed in white light are such closed field regions and have been assumed to be the source region of CMEs (Hundhausen, 1993).
		In addition to helmet streamers that form the coronal streeamer belt or the heliospheric current sheet, there are large-scale closed field regions occured between coronal holes having like-polarity, as sketched in Figure 7.1 of Hundhausen's book (1972).
	sun.stanford.edu /~zhao/muri_m.html (1845 words)

	Space Weather
		Coronal holes are eaily seen as dark regions in xray images of the sun such as the one to the left.
		Observations by the Ulysses mission of the fast flows associated with coronal holes compared to simultaneous observations by the Yokhoh mission of the coronal holes in soft xrays.
		In this location, the coronal holes spray the Earth with high speed plasma streams, like a powerful garden sprinkler, and are responsible for generating space weather storms that recur in intervals of 27 days as the coronal hole rotates back over the limb of the Sun.
	www.windows.ucar.edu /spaceweather/aoss335_activesun9.html (281 words)

	NGDC/WDC STP, Boulder-Solar Corona Data via FTP from NGDC
		Coronal Holes were first noted as M regions that produced periodic geomagnetic disturbances.
		Coronal Holes are almost permanently visible on solar poles, except at the time of the maximum of solar cycle, when polarity inversion occurs.
		August 1-September 30, 1995, Coronal Holes are measured on a daily basis from images taken from the Soft X-ray Telescope on board the YOHKOH Japanese spacecraft instead of the previous method of reducing the data solely from Kitt Peak Vacuum Telescope He 1083 nm images.
	www.ngdc.noaa.gov /stp/SOLAR/ftpsolarcorona.html (2196 words)

	ch6 (Site not responding. Last check: 2007-11-01)
		Skylab's continuous observations of coronal holes, coupled with measurements at Earth of the solar wind and geomagnetic wind, clearly established that coronal holes were the long-sought source of recurrent solar wind disturbances that buffet the upper atmosphere of Earth, making possible dramatic improvement in the prediction of the effects of the Sun on Earth.
		Coronal holes are a recent discovery of solar physics; they are not readily apparent in the photosphere or chromosphere, and are subtle features in coronagraph data or in pictures of the corona made at the time of eclipse.
		At the limb of the Sun the hole is marked by sudden spreading and fading of the bright ring of coronal ultraviolet emission.
	history.nasa.gov /SP-402/ch6.htm (8383 words)

	APOD: 2002 February 7 - Coronal Hole (Site not responding. Last check: 2007-11-01)
		Studied extensively from space since the 1960s in ultraviolet and x-ray light, coronal holes are known to be the source of the high-speed solar wind, atoms and electrons
		this coronal hole, one of the largest seen so far in the current solar activity cycle, extends from the south pole (bottom) well into northern hemisphere.
		Coronal holes like this one may last for a few solar rotations before the magnetic fields shift and change configurations.
	antwrp.gsfc.nasa.gov /apod/ap020207.html (175 words)

	Earth Changes TV - A Coronal Hole Targets Earth (Site not responding. Last check: 2007-11-01)
		Coronal holes are easy to spot by looking at the Sun through an x-ray telescope.
		The solar wind flows away of the Sun in all directions, not just from coronal holes, but the wind speed is high (up to 800 km/s) over coronal holes and much lower (300 to 400 km/s) elsewhere.
		The coronal hole visible on the sun now is at least 7 months old.
	www.earthchangestv.com /breaking/February2000/0224coronal.htm (398 words)

	SOHO PICK OF THE WEEK (Site not responding. Last check: 2007-11-01)
		Coronal holes appear as dark areas of the corona when viewed in ultraviolet light and in X-rays.
		Coronal holes are the source of strong solar wind gusts that carry solar particles out to our magnetosphere and beyond.
		These low-latitude coronal holes are responsible for the high-speed solar wind streams that sweep through the plane where the planets orbit -- and thus have a direct affect on "space weather" near the Earth.
	soho.esac.esa.int /pickoftheweek/old/16may2003 (355 words)

	Space Photos » Blog Archive » Elongated Coronal Hole (Site not responding. Last check: 2007-11-01)
		Coronal holes appear as dark area of the corona when viewed in ultraviolet light and in X-rays (seen here traversing down the upper half of the Sun in ultraviolet light).
		This coronal hole area is one of the largest ones seen over the past year.
		Coronal holes are responsible for the high-speed solar wind streams that sweep through the plane where the planets orbit — and thus have a direct affect on “space weather” near the Earth.
	jtintle.wordpress.com /2005/12/31/elongated-coronal-hole (351 words)

	Blowing in the Solar Wind (Site not responding. Last check: 2007-11-01)
		Coronal holes are found at the north and south poles of the Sun, where the magnetic field lines are open.
		Coronal holes are found where there are large regions of these so-called open field lines, that is at the poles of the Sun.
		Coronal holes can be seen in pictures of the Sun which show the hot gas in the corona.
	www.sunblock99.org.uk /sb99/people/JInsley/sb99_win.html_keep1 (1166 words)

	The Quiet Sun
		At coronal heights, filaments are embedded in a ``filament cavity'', a volume of lower coronal density.
		Prominent polar coronal holes appear during the decline to solar minimum, and then wane and disappear as the Sun returns to maximum levels of activity.
		Hence the structure and evolution of coronal holes, and the rôle they play in modulating the IPM throughout the solar cycle, is of great interest.
	www.cv.nrao.edu /vla/upgrade/node29.html (918 words)

	The Sun, Corona, and SPM
		The polar coronal holes are growing in size at this time and the global structure of the corona often appears “tilted” away from the rotation axis (N).
		Coronal holes are either absent or very small so that Solar Probe would have a negligible probability of encountering one.
		The corona is dominated by large equatorial streamers, polar coronal holes which extend down to mid-latitudes at the photosphere and nearly to the equator beyond a few solar radii, and CMEs occur at a rate of approximately one per day.
	science.msfc.nasa.gov /ssl/pad/solar/suess/SolarProbe/Page2.htm (1354 words)

	The Sun - 3
		Coronal mass ejections are giant magnetic bubbles that expand to nearly the size of the Sun itself as they leave the low corona.
		Earth is affected by the radiation and particles that solar flares and coronal mass ejections release.
		The magnetic field of the Sun is relatively weak around coronal holes and thus allows particles in the solar wind to escape.
	www.crystalinks.com /sun3.html (3568 words)

	Solar Wind (Site not responding. Last check: 2007-11-01)
		During the declining and minimum phases of the solar cycle, the solar wind is dominated by high-speed (500-800 kilometers per second) flows emanating from coronal holes -- regions of low coronal density and temperature where the magnetic field is weak and the field lines are open to interplanetary space.
		Coronal holes (the dark regions evident on the Sun's disk in the Yohkoh x-ray image on the right) occur both at low latitudes and at the poles; the polar holes are largest at solar minimum, extending equatorward and often merging with low-latitude holes of the same magnetic field polarity.
		In the ascending phase of the solar activity cycle and at solar maximum, the average solar wind speed slows, as the polar coronal holes shrink (and even disappear) and the high-speed flows narrow and weaken.
	pluto.space.swri.edu /IMAGE/glossary/solar_wind.html (638 words)

	Earth Change News on Earth Changes TV on the Web
		Coronal holes are regions where the corona is dark.
		Coronal holes are associated with "open" magnetic field lines and are often found at the Sun's poles.
		The high-speed solar wind is known to originate in coronal holes.
	www.earthchangestv.com /breaking/September2000/0914coronal.htm (134 words)

	Surprisingly long-lived coronal hole (Site not responding. Last check: 2007-11-01)
		Since the 1960s coronal holes have been identified as the source of high-velocity solar wind streams.
		When the spacecraft Mariner 2, which confirmed that high-speed solar winds originate from coronal holes, monitored solar wind patterns between 1962 to 1974, the longest-lived jet that it found lasted for 14 months.
		The first evidence of the long-lived coronal hole came from the Ulysses spacecraft in the early 1990s.
	www.stanford.edu /dept/news/relaged/951213coronal.html (287 words)

	Coronal holes [Oulu] (Site not responding. Last check: 2007-11-01)
		Coronal holes (Altschuler et al., 1972; Munro and Withbroe, 1972) are "dark" coronal regions of the Sun with open magnetic field structure.
		The fast-speed solar wind originates form the coronal holes (e.g., Krieger et al., 1973), and accordingly they are considered the main reason for the "recurrent" type of geomagnetic activity.
		Krieger, A. Timothy, and E. Roelof, A coronal hole and its identification as the source of a high velocity solar wind stream, Sol.
	www.oulu.fi /~spaceweb/textbook/coronal_holes.html (136 words)

	Genesis Web Science Document G: Solar Wind Properties
		Coronal holes are regions of the solar corona with open or unipolar magnetic fields and anomalously low density which appear dark in x-ray images of the Sun.
		The "quiet corona" between the holes and the streamers may also lead to slow, interstream flow; alternatively, the entire quasi-stationary solar wind may originate only in coronal holes and streamers whose flows expand laterally to fill all solar latitudes and longitudes.
		The squares are coronal hole data; the circles and triangles are interstream data, while the + and crosses are CME data.
	www.gps.caltech.edu /genesis/DocumentG.html (4852 words)

	SII 19Ion heating due to plasma microinstabilities in coronal holes and the fast solar wind
		It is widely thought that the heating of ions in coronal holes and the fast solar wind is due to cyclotron resonant damping of ion cyclotron waves.
		We suggest that the source of the waves in the coronal holes is intermittent electron heat flux produced by nanoflares at the coronal base.
		Any mechanism of wave generation in coronal holes has to be able to provide the heating very close to the Sun, within several solar radii.
	www.arcetri.astro.it /~solwind/abstract/node106.html (382 words)

	Space Weather Research Explorer: Space Weather and You
		The sun is continually releasing hot gases from its surface, a steady stream of particles—mostly protons and electrons—known as the solar wind.
		Coronal holes are places where magnetic field lines don’t close back on themselves, but instead stick straight out into space.
		Coronal holes appear as dark spots in ultraviolet pictures of the sun.
	www.exploratorium.edu /spaceweather/holes.html (205 words)

	Space Weather Research Explorer: Space Weather and You
		Coronal holes are easy to spot in pictures taken of the sun using extreme ultraviolet light (EUV).
		In these pictures, coronal holes show up as dark spots, because the trapped hot gas that would normally emit EUV light has been blasted into space by the particles exiting through the coronal hole.
		Only coronal holes near the sun’s equator—that is, holes pointing toward us—are likely to have effects here on earth.
	www.exploratorium.edu /spaceweather/holes_bigpic.html (169 words)

	ScienceDaily: Holes In Sun's Corona Linked To Atmospheric Temperature Changes On Earth (Site not responding. Last check: 2007-11-01)
		Coronal holes are, literally, gaps in the Sun's outer atmosphere through which the stream of hot, supersonic particles known as the solar wind pours out into space to engulf the entire planetary system.
		Regardless, the percentage of the Sun's surface covered by coronal holes seems to be a fairly accurate indicator of temperature in the Earth's troposphere over months or years.
		Associated with solar coronal mass ejections, coronal holes, or solar flares, a geomagnetic storm is caused by a solar...
	www.sciencedaily.com /releases/2000/03/000315080417.htm (1900 words)

	Coronal Holes/Solar Wind Posters - Solar Physics Division - AAS [SP]
		The VSM estimated coronal hole images are derived from daily full-disk photospheric magnetograms and He I 1083 nm spectroheliograms using an automated coronal hole detection algorithm.
		Study of small-scale dynamic events is important for solving the problem of coronal heating in the regions and for understanding whether the heating process is different in coronal holes than in quiet regions.
		In 2005, the polar coronal holes have not yet evolved to the fully quiescent minimum state seen in 1996-1997, though the next solar minimum is expected to occur in about 1.5 to 2 years.
	www.agu.org /meetings/sm05/sm05-sessions/sm05_SP51B.html (2051 words)

	SOHO PICK OF THE WEEK (Site not responding. Last check: 2007-11-01)
		Coronal holes appear as dark areas of the corona when viewed in ultraviolet light.
		Coronal holes are often the source of strong solar wind gusts that carry solar particles into space.
		The magnetic field lines in a coronal hole extend out into the solar wind rather than coming back down to the Sun's surface as they do in other parts of the Sun.
	sohowww.nascom.nasa.gov /pickoftheweek/old/12sep2002 (286 words)

	A skinny but robust coronal hole
		A coronal hole is a dark region of the corona from which coronal magnetic field lines open out into interplanetary space.
		This coronal hole, although skinny, was not frail.
		We've learned that there is almost no limit to the size of a coronal hole, perhaps, but that various factors limit the visibility of skinny ones.
	solar.physics.montana.edu /nuggets/2001/011116/011116.html (640 words)

	SPACE.com -- Space Weather Forecast: Coronal Holes Allow Solar Raygun to Zap Earth
		The dark shape toward the sun's upper left is a coronal hole.
		A series of enormous holes in the sun's corona have been causing disturbances in the Earth's magnetic field, and their effects are likely to continue for the next several weeks.
		Images at the right show a large coronal hole in the upper left of the solar disk.
	www.space.com /scienceastronomy/solarsystem/coronal_hole991019.html (636 words)

Try your search on: Qwika (all wikis)