Solar dynamic loops reveal a simultaneous explosion and implosion, plus evidence for magnetic reconnection

Jul 02, 2013
Image from NASA’s Solar Dynamic Observatory (SDO) at 17.7 nanometres showing the flaring active region on 9 March 2012. The coronal loops that contract during the flare are indicated by the labels L1 to L4, outer to inner. Credit: NASA/SDO/University of Glasgow.

(Phys.org) —Movies of giant loops projecting from the surface of the Sun are giving new insights into the complex mechanisms that drive solar flares and Coronal Mass Ejections (CMEs). These eruptions release vast energy and electrically charged particles that can affect the Earth through space weather. Imagery from NASA's Solar Dynamics Observatory (SDO), used in two separate studies, shows the dynamics of loops before, during and after eruptions. Results have been presented at the National Astronomy Meeting in St Andrews.

Coronal loops are giant magnetic arches filled with hot plasma at temperatures of over a million degrees Celsius. The structures are anchored in the dense , the visible surface of the Sun. The loops form the building blocks of the corona, the halo surrounding the Sun that can be seen during a . They are that oscillate back and forth after explosive events such as .

Researchers from the University of Glasgow observed four groups of loops that contracted rapidly during a flare on 9 March 2012. The loops had a 'staggered start' to their collapse, showing delays of 60–80 seconds from the inner to the outer loops.

"This event is a great example of a simultaneous implosion and explosion," said Dr Paulo Simões. "Our interpretation is that energy is transferred from the magnetic field to power the flare, leaving a pocket of reduced magnetic support that causes an implosion. The staggering between the loop contractions is caused by the time delay needed for the 'information' about the loss of support to travel outwards."

Version of same image of active region with frame superimposed showing time evolution of the heights of the collapsing loops (taken through the white line drawn across the imploding loops) showing the cleat collapse and oscillations of the bright structures around 03:40 UT on 9 March 2012. Credit: NASA/SDO/University of Glasgow

The loop contractions are triggered at the same time as the flare begins emitting intense X-rays and microwaves. The three outer loops show clear oscillations even as they contract, with distinct periods and phases. After being compressed by the collapsing loops, the flaring loops oscillate until they find a new equilibrium, as indicated by the X-ray emission from the hot plasma. During the contraction a wave blast revealed by extreme ultraviolet radiation spreads away from the source of the flare.

"This presents an intriguing picture of how magnetic energy is moved rapidly around the solar corona during a flare," said Dr Simões.

Flares and CMEs are thought to be driven by a process called , in which magnetic field lines in plasma break and then re-join to field lines flowing in the opposite direction. Energy that has built up over days or months is released in just a few minutes.

This video is not supported by your browser at this time.
Animation showing time evolution of the collapsing loops observed by SDO on 9 March 2012 Credit: NASA/SDO/University of Glasgow

In a separate study, a team from the University of Warwick has observed the first evidence that loop oscillations are driven directly by magnetic reconnection processes.

"The structure and dynamics of the solar corona can be imaged in exquisite detail and over an unprecedented range of temperatures by SDO. Oscillating loops are a useful tool for probing conditions in the corona. This offers a unique opportunity to discover the tell-tale signatures of magnetic reconnection," said Rebecca White, who presented the findings on Tuesday 2nd July.

The Warwick team used SDO data to study the behaviour of loops following two eruptions: a CME on 3 November 2010 and a solar flare on 8 May 2012. With the first eruption, they saw a coronal loop form below the bubble of material ejected during the CME. There appeared to be a strand connecting the CME with the top of the loop. Unusually, parts of the loop were observed to oscillate in different directions about a central pivot point.

"The loop appears to twist about a fixed point along its length. Not only is the form of this oscillation highly unusual but the coronal loop has a temperature of between 9 and 11 million degrees - this is much hotter than most loops we see, which are generally between 1 and 3 million degrees. This extreme heat has been generated by the reconnection processes," said White. "For the first time we can see a direct link between the reconnection process itself, causing the formation of the loop below the ejected bubble, and the oscillations of the loops."

This video is not supported by your browser at this time.
SDO false-colour composite movie of solar flare event on 8 May 2012 showing anti-phase oscillations of coronal loops. Credit: NASA/University of Warwick

The second observation showed two separate but adjacent loops oscillating in opposite directions to one another. Previous observations have shown loop oscillations caused by blast waves emanating from the flare, however this pushes the loops in a single direction.

"Again, this cannot be explained by a blast wave since this would push both loops in the same direction. We think that the oscillations here are a direct result of the flare reconnection process changing the structure of the corona between the loops and sucking them towards each. These observations demonstrate that loop oscillations are a valuable tool for studying 3D reconnection processes at work," said White.

Explore further: After early troubles, all go for Milky Way telescope

More information: R.S. White, E. Verwichte & C. Foullon, First observation of a transverse vertical oscillation during the formation of a hot post flare loop, A&A, 545, A129 (2012)

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User comments : 26

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cantdrive85
1.4 / 5 (11) Jul 02, 2013
"Magnetic reconnection is pseudo-science" Hannes Alfven

And so too is this nonsense above...
GSwift7
4.3 / 5 (10) Jul 02, 2013
Magnetic reconnection is pseudo-science" Hannes Alfven


Unfortunately for him, his work and opinions were crippled by the poor observations of his time. If only he had known what we know now.
DonGateley
3 / 5 (6) Jul 02, 2013
Exactly what is broken and reconnected? There are no such physical things as magnetic lines. There are magnetic fields which can be described by vectors. A line is just a path through the field which minimally changes the vector's direction as you move along its length. You can pick any point in the field and a single such line passes through it. It is a mathematical abstraction. Not something real. How can it break and reconnect? Maxwell would roll his eyes.

It would mean that as you followed along the line the field would suddenly end. Absurd.
LarryD
5 / 5 (1) Jul 02, 2013
It may be that the writer uses the unfortunate word, 'break' for this process which I have seen elsewhere and so may be the general accepted term. Magnetic reconnection is, as I understand it, is not well understood in plasma physics but apparently happens when different anti parallel magnectic fields 'overlap' (not sure I've used the correct term) where an exchange of energy takes place (also with the plasma). After a few seconds the 'overlaps' disengage and return to their separate states. Also, as I understand it, Maxwell's equations are used (Del curl B, I think) as well as other electro/mag laws involving resistivity.
Anyone elaborate on this?
cantdrive85
1.4 / 5 (9) Jul 02, 2013
Magnetic reconnection is pseudo-science" Hannes Alfven


Unfortunately for him, his work and opinions were crippled by the poor observations of his time. If only he had known what we know now.

It has nothing to do with "poor observations". It's the notion, as pointed out by DonGateley, a magnetic "field line" is not a physical thing which can break.
"A magnetic field line is by definition a line which is everywhere parallel to the magnetic field. If the current system changes, the shape of the magnetic field line changes but it is meaningless to speak about a translational movement of magnetic field lines." - Alfvén, op cit, p.12
cantdrive85
1 / 5 (10) Jul 03, 2013
Magnetic reconnection is, as I understand it, is not well understood in plasma physics but apparently happens when different anti parallel magnectic fields 'overlap' (not sure I've used the correct term) where an exchange of energy takes place (also with the plasma).


Magnetic reconnection (MR) has no place in plasma physics, it only resides in astrophysicists wild fanciful minds. In plasma physics, the process of an exploding double layer (DL) is a well understood process that was discovered by Hannes Alfven over 70 years ago. Astrophysicist are trying to "reinvent the wheel" here while ignoring nearly 200 years of ongoing research of electrical phenomenon. Alfven describes DL's and "magnetic reconnection" here;
http://kth.diva-p...XT01.pdf

Alfven was acknowledged with his Nobel 30 years after his discovery, being this paper was written in 1985 astrophysicists may catch on to this in the next few years. Then again...

LarryD
4.7 / 5 (3) Jul 03, 2013
cantdrive85, don't agree with you. Astronomy texts give Alfven credit but then you can't say they are re-inventing something just because they use said theories. I cannot find in the document 'diva-p... ' the term magnetic reconnection but can find 'merg' & 'reconnect'.
Another point about this document that while Alfven does deny the 'force lines' not being physical, continues to use the terminology himself.
I do, however, concur that the article does not mention Alfven and should do; almost looks like a remake of his work but using actual photographs.
I cannot comment on the video as they will not run (on my computer)
cantdrive85
1 / 5 (8) Jul 04, 2013
Astronomy/astrophysical texts acknowledge him for Alfven waves and MHD, yet they don't heed his warnings about the misuse of MHD and magnetofluid models in describing astrophysical plasmas.
Merge, reconnect, reconnection, it's all the same pseudo nonsense.
Dr.Don Scott, professor of EE goes into it further here (page 8)
http://electric-c...nder.pdf

What these "scientists" are analyzing is a circuit collapsing, and all of the inductive energy carried in the circuit is being released in an explosive event. These events need to be dealt with using particle and circuit models, the magnetofluid models used by astrophysicists do not apply to these phenomena.
LarryD
4 / 5 (1) Jul 04, 2013
Okay cantdrive85 I agree with you on some points but not on others. The SSM does say that most neutrinos are produced from p-p fusion, perhaps more correctly as H1,1 + H1,1 (can't type the suffixes correctly) to He1,2 + e(^+) + v so in some respects both Thompson and Scott are right and both are wrong too depending how one views the argument. Neither of them appear to give to full description of their point.
I must say that I am at a bit of loss when it comes to the '...field lines...' because I appreciate that the 'lines' aren't real but just 'on paper' representations. Some texts even give a series of dots but we need some form 'intuitive help' as long as we remember in reality they don't exist (in the same way that numbers are abstract). I assume that if I, as a layman, know this then surely scientsits do too. So I can't see what all the fuss is about.
It may well be that Alfven's MHD is not the correct model for astro topics but perhaps it is the best approximation we have.
cantdrive85
1 / 5 (8) Jul 04, 2013
No, particle and circuit models are the best approximation of plasma behavior. Alfven warned against using the magneto fluid models astrophysicists use, still they ignore the warnings.

I would also assume the scientists "know" "field lines" are a reification, a pedagogical tool. Yet here we are discussing reconnection. To be sure, reconnection is a purely astrophysical construct. Approach an electrical engineer to discuss "magnetic reconnection" and they will likely laugh in your face, yet astrophysicists have formalized such pseudo science to be a real phenomenon.
DonGateley
2.2 / 5 (6) Jul 04, 2013
"Approach an electrical engineer to discuss "magnetic reconnection" and they will likely laugh in your face..."

Pretty much exactly what I did and why I did it. :-)
LarryD
5 / 5 (1) Jul 05, 2013
I do appreciate your views but as a layman it's not as clear cut to me. For expl; I was looking at some book reviews (Electric Sky, Electric Universe, Thunderbolts etc) and while some reviews were in favour some weren't. One reviewer stated that he/she was a plasma researcher and done many experiments and said of Thornhill's Thunderbolt(...),[ which gets a positive review from Dr. Scott] I quote '...is total crap...' unquote. Assumimg the reviewer is truthful where does that leave a guy like me?
cantdrive85
1.3 / 5 (7) Jul 05, 2013
Read the books, decide for yourself. Then again, it may be a good idea to start with 'Cosmic Plasma' by Hannes Alfven or 'Physics of the Plasma Universe' by Anthony L. Peratt along with 'The Electric Sky' by Don Scott. Dr. Scott's solar theory is supported by the physics of plasma cosmology, although some points are speculative (admittedly), they are far less speculative than such things as black holes, dark matter, and other such mathematical constructs.

The EUT takes a more interdisciplinary approach that suggests mainstream science does not properly account for the true complexity of electromagnetism and the electric forces that permeate the Universe. It runs the gamut from mythology, cosmology, biology, geology, weather/climate, particle physics, etc... The real irony, PC and EUT are based upon empirical plasma research whereas the BBT and the "standard theory" are largely hypothetical and theoretical yet the supporters of the latter call the former cranks and crackpots. Humorous
LarryD
1.3 / 5 (4) Jul 05, 2013
cantdrive85, thanks. I have looked on amazon 'Physics of the Plasma Universe' by Anthony L. Peratt and very interested in the amount of content shown. Unfortunately, at over 400USD it is out of my price range as are several other books on this advanced topic. CP is also in 150-200USD range. My pension funds won't stretch that far for a single book (I do have expensive books but they were bought when I could afford it.) I will probably order ES & EU and also another that follows Alfven, 'The BB never happened'.
Protoplasmix
2 / 5 (4) Jul 07, 2013
Only when there's no matter present in the field is it as described in the preceeding comments, and even then it's very real and not abstract in the least. But when matter is present it affects the shape of the field, and the matter lines up in the field as the field is concentrated into lines by the matter. If changes occur to the object which is generating the field, old lines of matter break as new ones connect. This can be seen with iron filings on a piece of paper over a bar magnet, and now it can be seen with plasma in flux tubes on the sun.
LarryD
2 / 5 (2) Jul 07, 2013
Mmmm Protoplasmix, I don't know about other posts but not quite the same lines to which I referred. Yes obviously there is a 'line' pattern with iron filings but then the iron filings are following the direction of the field but they are not the field itself. I was actually talking about the 'lines' referred to in books and sometimnes the author reminds us that the drawn lines are just a way of indicating the strength of the field (thick or thin lines) and should not be construed as being the field.
'...plasma in flux tubes on the sun...'? Could you (or someone else) rephrase that?
cantdrive85
1 / 5 (6) Jul 07, 2013
Adding matter makes no difference in the definition of "field lines", reconnection remains pseudo mumbo jumbo.
Protoplasmix
1.5 / 5 (4) Jul 07, 2013
Adding matter makes no difference in the definition of "field lines", reconnection remains pseudo mumbo jumbo.

Thanks for not taking issue with my unconventional phrase 'matter lines.'

@LarryD, flux tube is another term for those awesome looking loops in the picture at the top of the article. I like the description 'magnetic arch' in the article, too. Some people take issue with the term 'field lines'. At least all can agree it's quite a complex subject as plasma is not a liquid or a gas. It's another state of matter.
cantdrive85
1 / 5 (5) Jul 07, 2013
From Wiki;
"A flux tube is a generally tube-like (cylindrical) region of space containing a magnetic field, such that the field at the side surfaces is parallel to those surfaces."

It's an answer that is no answer, it just leads to more questions. Why would a "generally tube like structure containing a magnetic field" have such a field? According to astrophysicists, these fields are "frozen-in" the plasma, more pseudoscience malarkey. On Earth, it's a well understood fact that time varying fields require electric currents, the same can be said for space plasmas. Those "generally tube like structure containing a magnetic fields" or flux tubes are in fact birkeland currents. No magic happens on the Sun, nor throughout the rest of the Cosmos for that matter, astrophysical magnetic fields are created just as they are here on Earth, with electric currents. As stated repeatedly, the magnetofluid models employed by astrophysicists are a mistake, particle and circuit theory apply here.

LarryD
4 / 5 (1) Jul 07, 2013
Protoplasmix, all areas of science contain sometimes diverse opinions and ideas and I don't post to be awkward or press my own point of view. I might not agree with some posts and I may have my own ideas on others (Time being one) but I enjoy to read other points of view...makes life so much more interesting. I am not religious (see other thread posts) and therefore don't respond very well to those who post religious views on a science forum. One can be a scientific theologian but keep them separate in discussions.
LarryD
5 / 5 (1) Jul 07, 2013

'It's an answer that is no answer....No magic happens on the Sun, nor throughout the rest of the Cosmos for that matter...'

cantdrive85 calm down, magic indeed! And is that intended to be a pun or is '...that matter...' another form of matter you have discovered Ha!
cantdrive85
1.2 / 5 (6) Jul 07, 2013
A description of the magnetic fields of those birkeland currents or "magnetic flux tubes" can be found here;
http://electric-c...elds.pdf

A description of why electric currents are necessary for magnetic fields is here;
http://electric-c...OAAJ.pdf
LarryD
1 / 5 (3) Jul 07, 2013
Thanks cantdrive85 as mentioned above I will purchase the mentioned books and hopefully the two links will be covered there.
Protoplasmix
1 / 5 (3) Jul 08, 2013
CD85, I understand you prefer to attribute a CME to the interruption of an electric circuit instead of reconnecting abstract field lines from the circuit, but I don't think the circuit to which you refer gets interrupted. I think the circuit is a convection current that simply gets displaced, causing the field to reconfigure. What's your view on that?
cantdrive85
1 / 5 (4) Jul 10, 2013
A convection current is created by a mixing of fluids. Plasma does not behave as a liquid any more than a solid does. Anyway, there is no convection to speak of, well at least not enough to make the internal combustion engine model of the sun work.
http://phys.org/n...ace.html

Alfven described all electric (or plasma) circuits as inherently explosive. If any part of the circuit is interrupted, most likely caused by a DL instability, all the inductive energy will be released at the point of disruption. The magnetic field will collapse because the circuit is broken, if the electric circuit reconnects then the electric current will create a new field.
Electric current = magnetism

The intense arc of plasma through the middle of the image is most likely the current pair or birkeland current creating the complex self-constricting magnetic field wrapped around it.
http://en.wikiped...rope.svg
Protoplasmix
1 / 5 (2) Jul 10, 2013
Thanks for the link - that article didn't say convection doesn't occur, it said they used helioseismology to determine that the convection is slower than numerical models predicted. Those results are based on probing to a depth of about 55000 km below the surface, or 8% of the sun.

It's obvious electromagnetism plays a role, but gravity and temperature are just as important in an accurate model.