Large coronal hole near the sun's north pole

Jul 20, 2013
Large coronal hole near the sun's north pole
The European Space Agency/NASA Solar and Heliospheric Observatory, or SOHO, captured this image of a gigantic coronal hole hovering over the sun's north pole on July 18, 2013, at 9:06 a.m. EDT. Credit: ESA&NASA/SOHO

The European Space Agency/NASA Solar and Heliospheric Observatory, or SOHO, captured this image of a gigantic coronal hole hovering over the sun's north pole on July 18, 2013, at 9:06 a.m. EDT. Coronal holes are dark, low density regions of the sun's outermost atmosphere, the corona. They contain little solar material, have lower temperatures, and therefore, appear much darker than their surroundings.

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. The activity cycle is currently ramping up toward what is known as solar maximum, currently predicted for late 2013. During this portion of the cycle, the number of coronal holes decreases. During solar max, the magnetic fields on the sun reverse and new coronal holes appear near the poles with the opposite magnetic alignment. The coronal holes then increase in size and number, extending further from the poles as the sun moves toward solar minimum again. At such times, coronal holes have appeared that are even larger than this one.

The holes are important to our understanding of , as they are the source of a high-speed wind of that streams off the sun some three times faster than the slower wind elsewhere. While it's unclear what causes coronal holes, they correlate to areas on the sun where magnetic fields soar up and away, failing to loop back down to the surface, as they do elsewhere.

Explore further: Coronal mass ejection to pass Earth, Messenger and Juno

Related Stories

Image: Coronal hole on the sun

Jun 06, 2012

(Phys.org) -- This image of a coronal hole on the sun bears a remarkable resemblance to the 'Sesame Street' character Big Bird. Coronal holes are regions where the sun's corona is dark.

Coronal mass ejection to pass Earth, Messenger and Juno

Jul 16, 2013

On July 16, 2013, at 12:09 a.m. EDT, the sun erupted with an Earth-directed coronal mass ejection or CME, a solar phenomenon that can send billions of tons of particles into space that can reach Earth one ...

Huge coronal hole is sending solar wind our way

Mar 14, 2012

An enormous triangular hole in the Sun’s corona was captured earlier today by NASA’s Solar Dynamics Observatory, seen above from the AIA 211 imaging assembly. This gap in the Sun’s atmosphere ...

Image: Holes in the Sun's corona

Jan 12, 2011

This Solar Dynamics Observatory image of the Sun taken on January 10 in extreme ultraviolet light captures a dark coronal hole just about at sun center.

Sun erupts with a CME toward Earth and Mercury

Jul 10, 2013

On July 9, 2013, at 11:09 a.m. EDT, the sun erupted with an Earth-directed coronal mass ejection or CME, a solar phenomenon that can send billions of tons of particles into space that can reach Earth one to ...

Recommended for you

NASA's space station Robonaut finally getting legs

3 hours ago

Robonaut, the first out-of-this-world humanoid, is finally getting its space legs. For three years, Robonaut has had to manage from the waist up. This new pair of legs means the experimental robot—now stuck ...

Sun emits a mid-level solar flare

Apr 18, 2014

The sun emitted a mid-level solar flare, peaking at 9:03 a.m. EDT on April 18, 2014, and NASA's Solar Dynamics Observatory captured images of the event. Solar flares are powerful bursts of radiation. Harmful ...

Impact glass stores biodata for millions of years

Apr 18, 2014

(Phys.org) —Bits of plant life encapsulated in molten glass by asteroid and comet impacts millions of years ago give geologists information about climate and life forms on the ancient Earth. Scientists ...

The importance of plumes

Apr 18, 2014

The Hubble Space Telescope is famous for finding black holes. It can pick out thousands of galaxies in a patch of sky the size of a thumbprint. The most powerful space telescope ever built, the Hubble provided ...

User comments : 33

Adjust slider to filter visible comments by rank

Display comments: newest first

cantdrive85
1.3 / 5 (12) Jul 20, 2013
While it's unclear what causes coronal holes, they correlate to areas on the sun where magnetic fields soar up and away, failing to loop back down to the surface, as they do elsewhere.


What they are proposing is "open field lines" or open circuits. Yes, it is a completely ridiculous notion and these "scientists" believe it as firmly as believe in their other pseudoscientific hulla baloo magnetic reconnection.
Shelgeyr
1.9 / 5 (9) Jul 20, 2013
"failing to loop back down to the surface"??? Are they serious?

They need to take a lesson or two in electrical engineering.

Magnetic fields which aren't closed? There ain't no such thang!
Protoplasmix
1.8 / 5 (5) Jul 21, 2013
Interesting that conditions in the sun produce waxing/wanning coronal holes at the poles, while other sets of conditions produce polar jets. Seems like drawing that contrast may help rank by order of importance variables like gravity, temperature, magnetic fields, electric current, plasma dynamics, etc.
GSwift7
4 / 5 (8) Jul 22, 2013
What they are proposing is "open field lines" or open circuits. Yes, it is a completely ridiculous notion


No, they aren't. These field lines do connect with something, possibly even looping back to sol eventually. They just become so diffuse that we can't trace their path. The strength of an EM field decreases as the cube of distance from its source, so the strength for any given area of space becomes virtually zero by the time it reaches Mercury. By then, an individual field will be so thoroughly mixed up with other fields that you cannot trace the origin of any particular part of the field vector.

Once again, you totally fail to understand this stuff.
cantdrive85
1 / 5 (10) Jul 22, 2013
These field lines do connect with something, possibly even looping back to sol eventually. They just become so diffuse that we can't trace their path.


Possibly?!?!?!? Where pray tell, would be the "other" possibility? BTW, "field lines" are no more real than the latitude and longitude "lines" that circle the Earth. Needless to say, you won't have to worry about tripping over them. Are you so stupid that you don't realize that by your above statement you are also suggesting "open field lines"? Strangely, the Sun's magnetic field, which according to YOU is "virtually zero" by Mercury, somehow still exerts it's will upon cosmic particles some 18 BILLION KM from the Sun.

Once again, who is it that fails to understand?
rug
3.7 / 5 (6) Jul 22, 2013
@cantdrive85 - I remember doing a experiment in elementary school they proves field lines do exists. Take a fairly strong magnet. Lay it down on a smooth surface. Then sprinkle iron shavings over and around the magnet. You will see the iron lines up with the line of the magnetic field around the magnet. I am starting to think due to your lack of basic elementary science knowledge that all of the theories you support are bunk science. You claim to know how plasma works and reacts. I don't think this is the case either. Lab experiments with plasma have shown it to travel along magnetic field lines. In fact, if there were no such thing as the magnetic fields no plasma experiments could have been done in the first place as the plasma does have a tendency to burn through most things. Since you seem to lack a basic elementary science education I suggest you find a site that would suite your level Here I'll give you a link even. Just because I am that nice of a guy http://kids.usa.gov/science
GSwift7
4.2 / 5 (5) Jul 22, 2013
Possibly?!?!?!? Where pray tell, would be the "other" possibility


Perhaps they form a loop with the positive and negative poles of the Earth's magnetic field, for example. Here's a wiki on Gauss's Law. You'll probably understand this subject a lot better if you read it, and follow the links to Maxwell's equations and such.

http://en.wikiped...%27s_law

BTW, "field lines" are no more real than the latitude and longitude "lines" that circle the Earth. Needless to say, you won't have to worry about tripping over them


I'm not sure why this seems so incredulous to you. We use vectors in math all the time. Do you have a problem when using a vector to describe a rocket launch? You know the vector of the rocket isn't a physical object, right? lol. A field line is a mathematical tool to describe the strength and polarity of a field at any given point in space, just like a vector that describes velocity.
GSwift7
4.2 / 5 (5) Jul 22, 2013
Take a fairly strong magnet. Lay it down on a smooth surface. Then sprinkle iron shavings over and around the magnet.


That's an illusion. The field is actually uniform, but the iron filings magnetize and stick to each other in clumps. That creates the illusion of banded lines within the field. The plasma in the corona does the same thing in the loops there. The coron is much more complex though because once the plasma starts to move through the field it generates its own field, which has the same polarity as the surrounding field, and so it strengthens the field along that path, and actually does create tubes where the field is stronger (according to state of the art theory). The tubes created by the plasma aren't field lines, but they do follow the path of field vectors if you could physically draw them in the field. I think they're calling them flux tubes, but someone could look that up for us?
rug
3.4 / 5 (5) Jul 22, 2013
That's an illusion. The field is actually uniform, but the iron filings magnetize and stick to each other in clumps. That creates the illusion of banded lines within the field.


Now why didn't I think of that? Alright, time fire my 1st grade teacher. lol

The tubes created by the plasma aren't field lines, but they do follow the path of field vectors if you could physically draw them in the field. I think they're calling them flux tubes, but someone could look that up for us?


This would be correct!
http://en.wikiped...lux_tube
barakn
not rated yet Jul 22, 2013
The strength of an EM field decreases as the cube of distance from its source, so the strength for any given area of space becomes virtually zero by the time it reaches Mercury. -GSwift7

True if the sun were a non-rotating dipole in a perfect vacuum, but this is not so. The magnetic field is entrained in the outward-moving solar wind in a configuration known as the Parker Spiral. Ideally it has a radial component that decreases as 1/r^2 and an azimuthal component decreasing as 1/r (!), although there are significant deviations from that in reality.
cantdrive85
1 / 5 (9) Jul 22, 2013
OK, I'm thoroughly confused, first you correctly identify "fields lines" as mathematical constructs, then in the next response you claim they're connected to the Earth's magnetic field.

Those "tubes of stronger field" or "flux tubes" (aka, Birkeland currents) are electric currents. The "tubes" are areas of higher density plasma, self confined and altered by the magnetic field that arises from the collective movement of the charged particles (electric current). Birkeland currents (BC) were found by Themis providing a direct connection to the Earth's poles from the Sun, but it is not "field lines" making the connection, it is helically twisting electric currents that make the connection.
http://www.youtub...lIMdJV5k

This idea that all these magnetic fields exist devoid of the prerequisite electric currents and electric fields is ridiculous. This paper shows how you cannot ignore the causal electric currents.
http://electric-c...OAAJ.pdf
cantdrive85
1 / 5 (8) Jul 22, 2013
Now why didn't I think of that? Alright, time fire my 1st grade teacher. lol


Personal responsibility, you've had plenty of time since the 1st grade to get it right.

Jayman
1 / 5 (3) Jul 23, 2013
Maybe the Sun is having its own version of global warming.
Protoplasmix
1 / 5 (2) Jul 23, 2013
For those having trouble visualizing magnetic field lines and the effects on these lines when matter is present in the field, perhaps the ways we accomplish magnetic shielding will be helpful. For example, see mu-metal at en.wikipedia.org/wiki/Mu-metal
GSwift7
1 / 5 (1) Jul 23, 2013
True if the sun were a non-rotating dipole in a perfect vacuum, but this is not so. The magnetic field is entrained in the outward-moving solar wind in a configuration known as the Parker Spiral. Ideally it has a radial component that decreases as 1/r^2 and an azimuthal component decreasing as 1/r (!), although there are significant deviations from that in reality


You're partly correct, but you should read the following page on the heliospheric current sheet:

http://en.wikiped...nt_sheet

The sun's magnetic field is only 100 times stronger than the 1/r^3 relationship would produce. That is still much weaker than your suggested 1/r^2 value. It is actually 1/r^3, but there's an amplification due to electrically charged particles being carried in the solar wind. To say that the sun's magnetic field doesn't obey Maxwell's equations would be incorrect. The deviation from this rule is simply the combined effect of overlapping fields, and is small.
GSwift7
1 / 5 (1) Jul 23, 2013
OK, I'm thoroughly confused


Yep, you got that right.

then in the next response you claim they're connected to the Earth's magnetic field.


Yep, about once every eight minutes, the Earth and sun connect magnetically. This is called a flux transfer event:

http://en.wikiped...er_event

Those "tubes of stronger field" or "flux tubes" (aka, Birkeland currents) are electric currents


I'm not sure if Birkeland currents have been positively identified there. I know we think there are Birkeland currents in flares, but the tubes are a bit different. Do you have a link?

This idea that all these magnetic fields exist devoid of the prerequisite electric currents and electric fields is ridiculous


yes, that would be rediculous, but the electic currents are fairly well understood, and nobody is denying them. It's an argument about thier nature, not whether they exist.
GSwift7
3 / 5 (2) Jul 23, 2013
Just a note about that previous comment:

When I said that the tubes are different than flares, I wasn't saying that there isn't a current in the tubes. I'm saying that it's not certain it's a birkeland current. The difference is like the difference between a tornado and a straight line wind. A birkeland current is a special situation with several characteristics that must exist before you can properly call it that. You know that though, right?

also, in regard to the 'argument' about the nature of currents in the solar system, it's not much of an argument any more. We've flown probes all around inside them and measured them in fine detail over long periods of time. Our dependence on satellits demands that we understand this.
rug
3 / 5 (4) Jul 23, 2013
Personal responsibility, you've had plenty of time since the 1st grade to get it right.


Personal responsibility? Please, it's an effect that I had seen with my own eyes so why would I question it? It's not like I work with magnetic fields so I have no need to bother. Now that GSwift pointed it out. It makes perfect sense with the way magnetism works. Therefore, I'm not going to bother looking it up as it has no relevance in my life anyway.

Just goes to show that something you have known your whole life can be completely wrong. Maybe you should think about that yourself? Lets face it. You have to go out on some pretty thin limbs to explain the "Plasma Universe" you keep talking about. When I first read some of your comments I got a bit curious so I followed you're links and found junk. Sure, one or two points make sense but the rest of it doesn't come close to fitting with what is seen. If the theory does not fit observations then it must be wrong. Science 101
cantdrive85
1 / 5 (7) Jul 23, 2013
The heliospheric current sheet is but a small portion of the overall magnetospheric current. Alfven's model is the best going in describing the observed circuits.
http://www.holosc...cuit.jpg
Let's remember Maxwell; Div B=0, which states that magnetic "field lines" are closed paths. That one equation proves "magnetic reconnection" cannot happen, nor can "open field lines".

Once again, the fluid models of plasma in which the "standard theory" uses are completely wrong, they cannot properly describe the Sun's observed magnetic field. The "Parker spiral model" of the heliospheric current sheet is just that, based upon fluid models that can't describe the observed phenomena such as the electric current that flows through it. It's time we moved on from the fluid models we know have been proven incorrect.
cantdrive85
1 / 5 (8) Jul 23, 2013
Yep, about once every eight minutes, the Earth and sun connect magnetically. This is called a flux transfer event:


You call it a "magnetic flux transfer event", I call it an electric current. To be sure, according to Maxwell, Div B=0, and as such there are no "magnetic field lines" connecting. The only other option is to acknowledge the self confined plasma in the "flux tube" is in fact an electric current.

It's an argument about thier nature, not whether they exist.


If you ask some, there are none and cannot be electric currents in space, and IF they do acknowledge them where it is unavoidable they claim they "don't do anything". Is it possible that these "flux transfer events" have zero appreciable effect upon say, the weather/climate? We know this phenomena can heat the atmosphere and affect satellite orbits, can and how does heating of the upper atmosphere affect weather patterns? Electric currents are there, and they do what they do on Earth, transfer energy.
GSwift7
3 / 5 (2) Jul 23, 2013
The only other option is to acknowledge the self confined plasma in the "flux tube" is in fact an electric current


Of course it is, but it's not looking like a birkeland current. It's just a regular current, as it doesn't have the characteristic helix except in the case of a flare. This still may not be a birkeland current, but a coincidence in stead. The jury is still out on that one, and people are working on figuring that one out.

Some of your electric universe principles are well-known in helio-physics and geo-physics. Those ideas actually originated in mainstream science and they aren't contested by mainstream science. That doesn't mean your attempts to extrapolate those effects up to interstellar or intergalactic scale are justified though. EM fields weaken too quickly over distance for your theories to be realistic. We've covered this many times before.

I see that you didn't bother reading the link to Gauss's law, which explains open field lines. Same ol' cantdrive. :(
GSwift7
3.7 / 5 (3) Jul 23, 2013
We know this phenomena can heat the atmosphere and affect satellite orbits, can and how does heating of the upper atmosphere affect weather patterns? Electric currents are there, and they do what they do on Earth, transfer energy


Once again, there's no need to wonder about mysterious unknown forces and such. We study this stuff every day. The ionosphere is just barely conductive, that's why it heats up; resistance. It has almost zero effect at ground level, where weather is dominated by convection and the water cycle.

You are over-estimating the magnitude of the solar electromagnetic flux around Earth's atmosphere by many orders of magnitude.
barakn
not rated yet Jul 23, 2013
Many, many studies from ancient http://onlinelibr...abstract to modern http://arxiv.org/...4832.pdf have found the sun's magnetic field follows a power law 1/r^p where p<2. If you're going to stick by a weakly written wikipedia article whose math you didn't even bother to double check, that's your own problem.

Also note correction to units in above formula, should read 1/215/1^2 * 10^-4 T...
cantdrive85
1 / 5 (6) Jul 23, 2013
It has almost zero effect at ground level, where weather is dominated by convection and the water cycle.
That's the belief, and a major reason for flaws in climate modeling. But climatologists aren't plasma physicists, so how would they know exactly how energy is transferred through a series of plasma double layers, via "flux tubes" and a complex magnetic field such that surround the Earth. They must rely on astrophysicist's models to determine how this process takes place, these same astrophysicists who are constantly surprised by new and unexpectedly complex features of space plasma. Alfven was quite concise in his assessment of the misuse of magnetofluid models, inre to space plasma and how those models have been shown to be incorrect by nuclear/plasma physicists decades ago. I propose it is the standard model that greatly underestimates... the POWER OF THE DARK SIDE... Little off track there, anyway, ...the energy transferred through this very dynamic plasma environment.
barakn
not rated yet Jul 24, 2013
Oops. I overwrote one post with another. The original said something like:

You're partly correct, but you should read the following page on the heliospheric current sheet:

http://en.wikiped...nt_sheet

The sun's magnetic field is only 100 times stronger than the 1/r^3 relationship would produce. That is still much weaker than your suggested 1/r^2 value. It is actually 1/r^3, but there's an amplification due to electrically charged particles being carried in the solar wind. To say that the sun's magnetic field doesn't obey Maxwell's equations would be incorrect. The deviation from this rule is simply the combined effect of overlapping fields, and is small. - GSwift7
I'm completely correct. The Earth-Sun distance is 215 solar radii, so a 1/r^2 reduction of a 10^-4 T field would be 1/215^2 * 10^-4 T = 2 * 10 -9 T = 2 nT. Per http://pluto.spac...MF.html, the magnetic field at Earth is 6 nT on average.
cantdrive85
1 / 5 (7) Jul 24, 2013
OK, I'm thoroughly confused


Yep, you got that right.


You get your argument straight, and I'll be good.

EM fields weaken too quickly over distance for your theories to be realistic. We've covered this many times before.


And you have shown that you are applying the incorrect power law and misrepresent the "vacuum of space" and how forces are transmitted through it. From world renown plasma physicist Anthony Peratt;

"In diffuse matter, which forms a major part of the universe, the motion of each individual particle is strongly controlled by the magnetic field. For example, a hydrogen ion in the solar wind with a thermal velocity of 20 kilometers per second in the interplanetary magnetic field of 5 nanotesla experiences a magnetic force of that is about 10^7 times stronger than the gravitational force from the Sun."

Gravity is a mere afterthought for that ion...

cantdrive85
1 / 5 (7) Jul 24, 2013
And what about galactic magnetic fields? Sadly the "dynamo effect" is not the answer:
http://www.univer...xpected/
"The center of the Galaxy has milligauss magnetic field strengths stretching 60 pc in length." Peratt
60 parsecs is pretty far.
And what about intergalactic magnetic fields, without galaxies present? This is a significant problem for standard theorists, there is no mechanism other that electric currents that can cause such phenomena, i.e. there are no magical dynamos in near nothingness.

That doesn't mean your attempts to extrapolate those effects up to interstellar or intergalactic scale are justified though

If doing so explains the phenomena, it seems silly not to do so, especially when your model requires "mysterious unknown forces and such" like dark matter and energy. The great advantage of plasma physics is the scalability of plasma behavior, it's no coincidence hurricanes look like galaxies.

GSwift7
3 / 5 (2) Jul 25, 2013
Many, many studies from ancient http://onlinelibr...abstract to modern http://arxiv.org/...4832.pdf have found the sun's magnetic field follows a power law 1/r^p where p<2. If you're going to stick by a weakly written wikipedia article whose math you didn't even bother to double check, that's your own problem


Ah, I see where your mistake is now. You're only looking at the interplanetary magnetic field along the ecliptic, where the solar wind carries its own field along the current sheet. The sun's dipole field itself obeys maxwell's 1/r^3 law. You can see this by measuring the solar magnetic field in the shadow of the Earth, or by measuring in places off-axis from the ecliptic.

You can also see the difference between the magnetic field of the solar wind and the actual magnetic field of the sun when you get to the edge of the heliosphere, where voyager is now.
GSwift7
3 / 5 (2) Jul 25, 2013
And you have shown that you are applying the incorrect power law and misrepresent the "vacuum of space" and how forces are transmitted through it. From world renown plasma physicist Anthony Peratt


No, you're applying a power law that is only relevant in a special cases to all cases. As I'm trying to explain to barakn, the magnetic field carried by the solar wind is a special case and it's only along the ecliptic. The reason it follows a 1/r^2 power law is because it is carried in a semi-flat disk. The magnetism is carried by the particles it is composed of (solar wind) along that disk. A disk expands with 1/r^2 density, which explains why the field decreases at that rate. The dipole field of the sun is negligable at 1 AU, so along the ecliptic the solar wind's magnetic field will be just about all you see. Objects without a solar wind, like a neutron star, will not have this current sheet effect, because there's no particle carrying the field outward.
GSwift7
3 / 5 (2) Jul 25, 2013
Here's a good paper by Prof. C. T. Russell of UCLA:

http://www-ssc.ig...rial.pdf

I think it is probably written with grad students in mind as a target audience, so it's a bit technical for most people, but should be within grasp of anyone who is well-versed in the vocabulary of this field.

60 parsecs is pretty far


196 light years is not very far, even if Peratt is correct about that, which I'm skeptical about.
barakn
not rated yet Aug 30, 2013
Ah, I see where your mistake is now. You're only looking at the interplanetary magnetic field along the ecliptic, where the solar wind carries its own field along the current sheet. The sun's dipole field itself obeys maxwell's 1/r^3 law. You can see this by measuring the solar magnetic field in the shadow of the Earth, or by measuring in places off-axis from the ecliptic. -GSwift7

Ah, I can see your mistake now. You think the Sun has some sort of distinct edge based on some sort of arbitrary definition. Do you think the Sun ends at the photosphere? That's an artifact of the ultraviolet cutoff imposed by both your mammalian eye and an absorptive atmosphere. The planets are clearly embedded in the outer reaches of the Sun.
barakn
not rated yet Aug 31, 2013
The strength of an EM field decreases as the cube of distance from its source, so the strength for any given area of space becomes virtually zero by the time it reaches Mercury. -GSwift7
Mercury. So you're the one that originally restricted it to the ecliptic. And no mention of a restriction to a dipole-only component, not the actual total magnetic field. When are you going to stop moving the goalposts? And what kind of garbage phrase is "The strength of an EM field decreases as the cube of distance from its source?" Quick, how does the strength of a magnetic quadrupole decrease?
Gmr
not rated yet Aug 31, 2013
[NECRO - C - C - C - COMBO - BREAKER]

More news stories

NASA's space station Robonaut finally getting legs

Robonaut, the first out-of-this-world humanoid, is finally getting its space legs. For three years, Robonaut has had to manage from the waist up. This new pair of legs means the experimental robot—now stuck ...

Cosmologists weigh cosmic filaments and voids

(Phys.org) —Cosmologists have established that much of the stuff of the universe is made of dark matter, a mysterious, invisible substance that can't be directly detected but which exerts a gravitational ...

Ex-Apple chief plans mobile phone for India

Former Apple chief executive John Sculley, whose marketing skills helped bring the personal computer to desktops worldwide, says he plans to launch a mobile phone in India to exploit its still largely untapped ...

Filipino tests negative for Middle East virus

A Filipino nurse who tested positive for the Middle East virus has been found free of infection in a subsequent examination after he returned home, Philippine health officials said Saturday.

Egypt archaeologists find ancient writer's tomb

Egypt's minister of antiquities says a team of Spanish archaeologists has discovered two tombs in the southern part of the country, one of them belonging to a writer and containing a trove of artifacts including reed pens ...

Airbnb rental site raises $450 mn

Online lodging listings website Airbnb inked a $450 million funding deal with investors led by TPG, a source close to the matter said Friday.