Loopholes discovered in Sun's magnetic belt

Loopholes discovered in Sun’s magnetic belt

(Phys.org)—The mystery surrounding how an electrically charged solar wind can be unleashed from around the Sun's equator – an area where strong magnetic fields should strap it to the surface – has been solved by an international team of researchers.

Using data from the Hinode telescope, researchers have been studying the 'slow' solar wind, which comes from the aptly named 'equatorial belt' of the Sun where the is strapped to the surface of our local star. 

The paradox has been that these equatorial regions are full of closed that are confined to the Sun, which should prevent gasses from escaping. Published today in the journal , the answer to how the slow solar wind escapes into the universe turns out to be linked to regions where the magnetic field vanishes altogether, regions called null points.

Team leader, Lidia van Driel-Gesztelyi (UCL Mullard Space Science Laboratory), explained: "The Sun is a magnetic star and we have known for a long time that the magnetic field in the atmosphere controls the flow of the gases – where they can and cannot go. At the poles of the Sun the magnetic field allows the gases to escape, but around the the gases should be trapped. 

"Our shows that that there are special configurations of the magnetic field that can undo the belt around the Sun's middle and provide the trapped gases with an escape route. Effectively opening up previously closed magnetic structures and releasing the gas they contain."

In 1958 it was proposed that the temperature of the solar atmosphere is so high that even the huge of the Sun cannot hold it down, resulting in a supersonic wind that constantly blows outward. 

This out-flowing solar wind is gusty and sometimes it blows fast, and sometimes slow. The source of the fast solar wind originates from regions where the Sun has very extended or 'open' magnetic field structures that reach out to vast distances in the solar system. The hot and electrically charged gases of the Sun's atmosphere are channelled along these magnetic field lines out into space.

The slow solar wind is twice as dense as the fast solar wind and more variable in speed. However, the Earth, and all other planets, spend most of their time immersed in the slow solar wind. Luckily most of the wind blows over us as we are protected our own magnetic field created inside the Earth. But planets like Venus and Mars – with no magnetic field – have their atmospheres stripped away.

The solar wind continues to blow out into the solar system until stopped by the pressure of the gas between the stars. 

Together, the closed and open regions of the Sun's magnetic field create a complex web that envelops the Sun in a series of structures resembling domes and drawn out threads. Since it is not possible to measure or see this web directly, the team created a computer model constructed from real data. The model allows the study of where and why the gases flow.

Lidia van Driel-Gesztelyi said: "The Sun's magnetic field and atmosphere are very different to what we experience at the Earth. The Sun's atmosphere is electrically charged which means that the particles are trapped by the magnetic field – the magnetic field acts as a tube along which the gases flow. But the magnetic fields themselves are dynamic. They can stretch out like elastic bands and also snap apart and then connect up with neighbouring magnetic fields."

In this study, the researchers found evidence that the magnetic web around the equator can consist of null points. Null points are interesting features and even though they are effectively empty regions, magnetic fields can pass through them. As the magnetic fields pass through they experience a change that turns them from being closed structures to open structures. During this process, gases can then be transported high enough to escape along these open magnetic structures that act as chimneys sending the of the solar atmosphere into the solar system.

Previous work by some of the team members showed how upward gas flows can be generated in the solar atmosphere in the first place. Combining this with the new results means that the team are now able to say which regions of the will produce gas flows that make it all the way out into to the solar wind, and which will be confined to the Sun, creating a unified model of the / slow flows.

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Image: Coronal hole on the sun

Journal information: Solar Physics

Citation: Loopholes discovered in Sun's magnetic belt (2012, October 10) retrieved 17 September 2019 from https://phys.org/news/2012-10-loopholes-sun-magnetic-belt.html
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Oct 10, 2012
Most people will definitely be more stupid after reading this nonsense. Clearly these "scientists" have zero real world knowledge of circuit theory or electromagnetism in general, is it any wonder why they are perplexed and amazed at every new observation. Open magnetic field lines? Gases on the Sun? Enough said!

Oct 10, 2012
Are you guys daft? You're telling me no one til now has seen those? You've got to be freaking kidding me!

Oct 10, 2012
Also from the article.

"The solar wind continues to blow out into the solar system until stopped by the pressure of the gas between the stars".

Are you freakin kidding me? Who thinks up this BS?

Those are our "brilliant" NASA "scientists".

"Students using astrophysical textbooks remain essentially ignorant of even the existence of plasma concepts, despite the fact that some of them have been known for half a century. The conclusion is that astrophysics is too important to be left in the hands of astrophysicists who have gotten their main knowledge from these textbooks. Earthbound and space telescope data must be treated by scientists who are familiar with laboratory and magnetospheric physics and circuit theory, and of course with modern plasma theory."
[Lamenting the traditional neglect of plasma physics]
— Hannes Alfvén

Oct 10, 2012

Maybe reread the article, allow for the inept language, and back off the white-hot alternative cosmology bias.

There is nothing in this article that isn't part of our current theory and observation of the Sun.

Oct 11, 2012
The article says the sun has "very extended or 'open' magnetic field structures". They are clearly just talking about the lines that reach far out and are in a sense, 'open'. The single quotes there are important.

Oct 11, 2012
So, I get it. If I used 'single quotes', I can insert whatever I decide to describe scientific basics? Sorta like, The moon is made of 'cheese'. Saturn has 'hula hoops' around it. The moving 'volcanoes' on Io is actually evidence of EDM. In no sense is a magnetic field 'open', and to even suggest it shows an incomplete understanding of magnetospheric theory. After rereading the article, it is clear she's doesn't know her ass from a corona hole in the sun.

Oct 14, 2012
To iterate, they say "very extended or 'open' magnetic field structures". I don't see why you would want to fight over semantics so much. The important thing here is that there are some very extended structures; some of the field lines go way out of the solar system, so for all intents and purposes you can call them open if you want. It is the same when astronomers say stars are at 'infinity'. For the purposes of focusing of light, the light is basically coming parallel. The important thing is to be aware of this distinction, and I see no reason to believe the author is unaware of this.

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