Researchers make magnetic fields breakthrough

Aug 20, 2010
Researchers make magnetic fields breakthrough

(PhysOrg.com) -- Researchers at the University of Dundee have made a breakthrough in the study of magnetic fields, which enhances our understanding of how stars, including the Sun, work.

The team from the Magnetohydrodynamics research group in the School of Engineering, Physics and Mathematics used state-of-the-art computer simulations of evolving plasmas in the Sun's atmosphere.

By following how the magnetic field and the plasma interact, they have uncovered new rules that govern what evolutions are possible. Knowing the basic rules behind the apparently complex gives the team hope of predicting how it will behave.

Magnetic fields cannot be directly seen, felt or tasted, but they are a ubiquitous force of nature. The neat pattern of magnetic "field lines" from a bar magnet is well-known from school physics experiments. Indeed, the magnetic field of the Earth itself has a similar pattern on a much larger scale, which is what enables navigation by compass.

But magnetic fields are not always so ordered. Telescopic pictures of the Sun's lower atmosphere taken in extreme-ultraviolet light, outside the , reveal the shape of the magnetic field lines because the plasma particles emitting the light are guided by magnetic forces and move along the magnetic field lines.

These images often reveal braiding and tangling of the field, in a manner that would render a compass useless. The fact that the magnetic field lines are tangled like spaghetti means that the plasma in the Sun's atmosphere is not free to move around however it pleases and that vast quantities of energy can be locked in the magnetic field, because tangled fields have more energy than ordered fields.

Scientists believe that this energy is responsible for heating the ’s atmosphere to million-degree temperatures, but how this works in detail is a longstanding puzzle in . The Dundee team hope their discovery will give us a better idea of just how this energy is released.

'Using these , we have studied braided magnetic fields and made a significant advance in understanding how they evolve over time,' said Dr Gunnar Hornig, one of the paper’s authors.

'You can observe magnetic fields on the Sun with satellites and see that these structures are often braided. That is they are not just simple loops, but these loops interlink.

'These structures are not static. They evolve because the Sun is not a rigid body but essentially a plasma ball of gas. It kind of boils, and the motion on the surface changes these magnetic structures. They start to move them around and sometimes the braiding is increased. And if certain critical conditions are met then these structures start to relax to something simpler.

'If you take a twig of a branch and start to twist it, then at some point it starts to break and the individual fibres break up. Something similar happens to these magnetic fields. Where it differs is that the evolutions we have been studying allow the broken fields to combine to form new structures.'

Having investigated how braiding works in a specific instance, the team will now switch their attention to examining how they work in more general, complex structures.

'We began by looking at braided magnetic fields in the Sun’s atmosphere,' explained Dr Anthony Yeates, one of the team members. 'We know that these magnetic fields break up and reconnect and we have now discovered new rules governing which evolutions are possible and how this is happening.

'This is fundamental research - part of the theory of astrophysical plasmas. It forms part of our attempts to understand how stars work, which enhances our understanding of how our own Sun evolves, and how it affects the climate and life on Earth.'

Their research has been published in the latest edition of Physical Review Letters, as a paper entitled 'Topological constraints on magnetic relaxation'.

The ongoing research project on quantifying magnetic fluxes started last October, and is funded by the Science and Technology Facilities Council.

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Provided by University of Dundee

4.7 /5 (28 votes)

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User comments : 12

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stm_wrp
2.9 / 5 (7) Aug 20, 2010
I would just like to say : crazy sauce. Imagine what the (nonscientific community) wacko's will come up with when they hear about this. "this tinfoil hat will braid the magnetic weave of your brain, making you RICHER$$"
JRDarby
4 / 5 (8) Aug 20, 2010
I'm just waiting for the "dense aether" crowd, complete with strange allusions to bubble-blowing and sandwiches, to claim that dense aether somehow explains all of this.
HoboWhisperer
3.4 / 5 (5) Aug 20, 2010
I thought I was the only one who thought that the comments trend towards bizzare here :)
Good to see I have company!
stealthc
1 / 5 (11) Aug 20, 2010
climate change pushers strike again -- this scientist should shut up, do his job, and avoid stating things outside of his realm of expertise as if it is fact.
bhiestand
4.2 / 5 (5) Aug 21, 2010
Yeah, over the years I've watched this place go from relatively sane scientists commenting on research to... absolute whackjobs spewing all sorts of garbage. It's been a said degenaration, but you're definitely not the only one to notice it.
Sonhouse
3.3 / 5 (3) Aug 21, 2010
I think every one of you previous posters need medical help. There was nothing in this article to cause your kind of rants. Any time they can figure out underlying rules about magnetic fields it can help understand many other fields, perhaps even fusion research like ITER. When basic research is done, nobody knows where it will lead 20 years down the line. You people are like 3rd graders going Nya Nya Nya. It's a disgusting display of attention seekerism.
Kedas
5 / 5 (1) Aug 21, 2010
This twisting and breaking of FIELDS doesn't that mean that it is a flow going from A to B?
So if it is a flow what is flowing there?

We do have light (includes magnetic fields) that is a flow (of waves or particles)

Xaero
2 / 5 (4) Aug 22, 2010
There is more detailed article about subject searched:

http://www.uksolp...-corona/
mgmirkin
2.3 / 5 (3) Aug 22, 2010
stm_wrp, JRDarby, HoboWhisperer, StealthC:

What kind of nonsense you guys yapping about? You appear to be the ONLY ones here spewing nonsense. 1of5 stars for all of you. If you have nothing USEFUL to contribute quit yer' bitching... Seriously!

Re: "braiding," this is a simple feature of parallel electric currents in plasma. They are long-range attractive and short-range repulsive, thus end up attracting and braiding/twisting around one another.

plasmascience.net/EM_forces.html
"The electromagnetic forces between two Birkeland currents, which are electric currents aligned along magnetic-field lines. These currents have parallel components that exert a long-range attractive force and circular components that provide short-range repulsion."

Nothing new here, except maybe to those not already familiar with a bit of plasma behavior.
mgmirkin
2 / 5 (4) Aug 22, 2010
P.S. "Magnetic Field Lines" are not real entities in 3D space. They are a draftsman's artifice on par with lines of elevation on a topographical map or millibars on a weather map.

Magnetic "field lines" are drawn closer togethe rwhere the field is stronger and further apart where the field is weaker. They are a VISUAL TOOL, nothing more.

Would you argue that lines of elevation "store elevation energy" that is released when an earthquake happens and the elevation lines "snap and reconnect?" Of course not. Rubbishy nonsense. Likewise, millibars do not
"store weather energy," etc.

Electric current configuration change. The magnetic fields they generate change. The "magnetic field lines" must be re-drawn at each instant. One line does not persist from one instant to the next. A completely new set of lines is generated each moment. There is no twisting, bending, twirling, coiling, snapping, or "reconnecting." Anyone who tells you differently is selling you a bill of goods.
mgmirkin
3 / 5 (6) Aug 22, 2010
A magnetic field is a continuous / infinite set of points each of which is a vector with direction, magnitude, and probably some other features. It is not composed of discrete threads, or lines or ropes, etc.

Ohh, and, while we're at it, there's no such thing as an "open" field line. All field lines must close. Yes, as with elevation maps, some lines do go off the page, but only because the page is not large enough. Zoom out, and the elevation "lines" can be seen to be continuous/complete on the largest scales. So it is with magnetic field lines. Anyone who talks about "open solar field lines" flapping in the breeze also doesn't know what they're talking about. Yes, the "field lines" may extend over great distances (off the page, so-to-speak), but they do not extend infinitely. They eventually loop back and "close." That's inherent to Maxwell's equations. (Part of the reason there are no magnetic monopoles).

(Magnetic Monopoles?)
farside.ph.utexas.edu/teaching/em/lectures/node35.html
Ravenrant
1 / 5 (1) Aug 29, 2010
Braided magnetic fields cause outbreaks of murder and insanity. This can't be explained by dense aether. Just the opposite, it explains dense aether.

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