Scientists crack 70-year-old mystery of how magnetic waves heat the sun

March 6, 2018, Queen's University Belfast
Credit: Queen's University Belfast

Scientists at Queen's University Belfast have led an international team to the ground-breaking discovery that magnetic waves crashing through the sun may be key to heating its atmosphere and propelling the solar wind.

The sun is the source of energy that sustains all life on Earth but much remains unknown about it. However, a group of researchers at Queen's have now unlocked some mysteries in a research paper, which has been published in Nature Physics.

In 1942, Swedish physicist and engineer Hannes Alfvén predicted the existence of a new type of wave due to magnetism acting on a plasma, which led him to obtain the Nobel Prize for Physics in 1970. Since his prediction, Alfvén waves have been associated with a variety of sources, including nuclear reactors, the gas cloud that envelops comets, laboratory experiments, medical MRI imaging and in the atmosphere of our nearest star – the sun.

Scientists have suggested for many years that these waves may play an important role in maintaining the sun's extremely high temperatures but until now had not been able to prove it.

Dr. David Jess from the School of Mathematics and Physics at Queen's University Belfast explains: "For a long time scientists across the globe have predicted that Alfvén waves travel upwards from the solar surface to break in the higher layers, releasing enormous amounts of energy in the form of heat. Over the last decade scientists have been able to prove that the waves exist but until now there was no direct evidence that they had the capability to convert their movement into heat.

"At Queen's, we have now led a team to detect and pinpoint the heat produced by Alfvén waves in a sunspot. This theory was predicted some 75 years ago but we now have the proof for the very first time. Our research opens up a new window to understanding how this phenomenon could potentially work in other areas such as energy reactors and medical devices."

A view of a sunspot on the solar surface, visible here as a dark collection of plasma with magnetic field strengths similar to those found in modern hospital MRI machines. However, it is the size of the sunspot, which is comparable to that of our own Earth (see the scale Earth depicted in the lower-right corner), that gives these structures immense power and energy. The recent work published in Nature Physics reveals first-time evidence for how a rare breed of magnetic waves, which originate within the centre of sunspots, can form shockwaves that heat the surrounding plasma by thousands of degrees. Credit: Queen's University Belfast

The study used advanced high-resolution observations from the Dunn Solar Telescope in New Mexico (USA) alongside complementary observations from NASA's Solar Dynamics Observatory, to analyse the strongest magnetic fields that appear in sunspots. These sunspots have intense fields similar to modern MRI machines in hospitals and are much bigger than our own planet.

Dr. Samuel Grant from Queen's comments: "By breaking the sun's light up into its constituent colours, our international team of researchers were able to examine the behaviour of certain elements from the periodic table within the sun's atmosphere, including calcium and iron.

A sunspot located towards the edge of the Sun, visible here as a dark collection of plasma with magnetic field strengths similar to those found in modern hospital MRI machines. However, it is the size of the sunspot, which is comparable to that of our own Earth (see the scale Earth depicted in the upper-right corner), that gives these structures immense power and energy. Extending upwards from the highly magnetic sunspot are field lines that can guide and direct dynamic motions from within the Sun's deepest layers. The recent work published in Nature Physics reveals first-time evidence for how a rare breed of magnetic waves, guided upwards from the surface of the Sun, can form shockwaves that heat the surrounding plasma by thousands of degrees. Credit: Emma Gallagher

"Once these elements had been extracted, intense flashes of light were detected in the image sequences. These intense flashes had all the hallmarks of the Alfvén waves converting their energy into , in a similar way to a supersonic aircraft creating a boom as it exceeds the speed of sound. The shock waves then ripple through the surrounding plasma, producing extreme heat. Using supercomputers, we were able to analyse the data and show for the first time in history that the Alfvén waves were capable of increasing plasma temperatures violently above their calm background."

Explore further: Observations to help astrophysicist understand sun's Alfven waves

More information: Samuel D. T. Grant et al. Alfvén wave dissipation in the solar chromosphere, Nature Physics (2018). DOI: 10.1038/s41567-018-0058-3

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11 comments

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Cusco
4.4 / 5 (13) Mar 06, 2018
And not a peep from the Electric Universe loonies. Go figure.
gculpex
1 / 5 (8) Mar 06, 2018
And not a peep from the Electric Universe loonies. Go figure.

Really? Takes a loonie to say someone is one.
There's nothing here to argue about!
Hannes Alfven has been reborn!
mackita
1 / 5 (8) Mar 06, 2018
H. L. Mencken: "For every complex problem there is an answer that is clear, simple, and wrong".

Sorry, but the solar corona cannot heat itself - with magnetic reconnection, shock Alphen waves etc. - or without it. IMO it's heat results from braking of solar neutrinos and scalar waves, which are prefferentially absorbed by accelerating charged particles and their magnetic fields. Similar effect we can also observe in atmosphere of large planets (Jupiter) and galactic bulge rich of dark matter.
cantdrive85
1.5 / 5 (8) Mar 06, 2018
These intense flashes had all the hallmarks of the Alfvén waves converting their energy into shock waves, in a similar way to a supersonic aircraft creating a boom as it exceeds the speed of sound. The shock waves then ripple through the surrounding plasma, producing extreme heat.

It's an electric discharge that transfers the energy too, not just mechanical.

http://electric-c...0Sun.pdf
granville583762
2.3 / 5 (3) Mar 07, 2018
there's our fusion reactor, pity we never copied it, we even use the same magnetic fields.
mackita
1.5 / 5 (8) Mar 07, 2018
The kooks weigh in
The secret of geniality is in (judging the) sources of information, as Einstein knew and has said. I for example know, that temperature of solar corona rises above sunspots, despite that they're free of Alfvén waves and colder than the rest of solar surface. In addition the same effect (high temperature of upper layers of atmosphere) occurs at the case of red dwarfs and large planets, which also cannot exhibit Alfven waves or magnetic reconnection events. So that the mechanism for their heating must reside somewhere else at least partially.

For supporters of Ptolemy epicycles their models also looked noncontroversial - the devil just was in their overlooked details (you know: order of Venus phases, Jupiter moon phases, Moon crater shadows and similar stuffs).
granville583762
1 / 5 (6) Mar 07, 2018
Magnetic toroidal currants in plasmoids create solar sunspot currant loops.
milnik
2.3 / 5 (3) Mar 08, 2018
Alfen was right in explaining the effect of magnetism on the current flow, which caused forces and thus some waves. But, if you know what magnetism is and how it occurs and what it does, it can almost certainly be explained. Why is space above the surface of the sun warmer than its surface? It can be difficult to understand.
Here's how it happens: high gravity deformed the atoms in the interior of the sun and the outer layer of the electron went out and formed an electric field. Due to the mutual relationship between free gluons in the plasma of the Sun and Aether, in which everything in the universe is "submerged," a very magnetic field arises, which in the electro field causes the movement of electrons through a space filled with various particles that exude the sun. Due to the motion of particles and electrons, heat electromagnetic waves are formed that warm up the space.
TrollBane
5 / 5 (4) Mar 09, 2018
"Magnetic toroidal currants in plasmoids create solar sunspot currant loops."

This illustrates the importance of spelling. By referencing what is an ingredient in a jam, you've placed yourself in a bit of a pickle.
Professor Plum
not rated yet Mar 10, 2018
Density and friction.
mackita
1 / 5 (1) Mar 11, 2018
Gas Giants' atmospheres are too hot. Jupiter, Saturn, Uranus & Neptune are far from the Sun so their upper atmospheres should be -73 °C, but they're about 700°C! I presume, in similar way like the solar corona, the excess of temperature can be explained by braking of dark matter particles (scalar waves and neutrinos) by charged particles in their atmosphere.

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