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

Posted: March 7, 2018 by oldbrew in research, solar system dynamics
Tags: ,

NASA image of the day: Sun’s quiet corona [credit: NASA/SDO]


‘Magnetic’ seems to mean ‘electromagnetic’ in this report. There’s a definition of an Alfvén wave here.

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, as Phys.org reports.

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.”

Continued here.
– – –
Science Daily: Discovery of Alfvén waves in the corona of the Sun [2011]

Comments
  1. Jim says:

    Not completely on topic, but there is one ecosystem on earth which does not obtain its energy from the sun: https://www.nationalgeographic.org/media/deep-sea-hydrothermal-vents/

  2. p.g.sharrow says:

    Everything in the Universe is the result of Charge in Motion, CiM .

    This matters, even Mater owes it’s existence to CiM. Gravity, Mass/Inertia and EMF are all the result of CiM.

    Any change of that motion results in a change in measurable characteristics because our sensors, detectors are based on field changes caused by changes in CiM in the detector.

    Charge changes cause change in motion. Change in motion cause change in charge.

    There is only charge, and a lack of charge. Binary, 1 and 0…pg

  3. pochas94 says:

    I used to think that chromospheric heating was caused by the unwinding of magnetic tubes as they were swept outward by the solar wind.

  4. Curious George says:

    “we have now led a team to detect and pinpoint the heat produced by Alfvén waves in a sunspot.” A sunspot is colder than a surrounding area. Lots of work still to do.

  5. Eric Johnson says:

    What mechanism(s) drives/maintains hydrothermal vents?
    From: https://oceanservice.noaa.gov/facts/vents.html
    Seems to me simplistic hand waving. Where’s the pressure gradient?
    Why isn’t “cold seawater” rejected by the warmed seawater immediately below (as it’s descending)?

  6. oldbrew says:

    Curious George says:
    “we have now led a team to detect and pinpoint the heat produced by Alfvén waves in a sunspot.” A sunspot is colder than a surrounding area. Lots of work still to do.

    Agreed it’s not a great explanation. From other sources it appears the idea is that the Alfvén waves drive heat away from the sunspot area – which then becomes cooler, as observed from Earth.

    That was what the intro here seemed to be saying – although the abstract may be saying something else!
    http://link.springer.com/article/10.1007%2FBF00156866

    From the free preview:
    The question which arises is whether the missing radiative energy of a sunspot can
    actually escape in the form of mechanical waves, and if so where does this energy
    finally get deposited?

    – – –
    SDO Spots Extra Energy in the Sun’s Corona
    July 27, 2011

    Like giant strands of seaweed some 32,000 miles high, material shooting up from the sun sways back and forth with the atmosphere. In the ocean, it’s moving water that pulls the seaweed along for a ride; in the sun’s corona, magnetic field ripples called Alfvén waves cause the swaying.

    http://www.nasa.gov/mission_pages/sdo/news/alfven-waves.html

  7. pochas94 says:

    If you check the PFSS graphics here
    https://sdo.gsfc.nasa.gov/data/
    you see that sunspots are a copious source of closed field lines, and my understanding is that charged particles would spiral around these field lines, traveling away from the sunspot, the charge depending on the polarity of the spot. This tells me that sunspots expel plasma from inside the spot, which would translate directly into a reduction in temperature. This Alfvén wave business seems to me to be gilding the lilly. Am I missing something?

  8. oldbrew says:

    pochas – it seems the Alfvén waves keep going upwards.

    The pertinent question is, why are there only upward-traveling waves in the moat in between the concentric halos?

    5. FAST-WAVE DAMPING AND ALFVÉN WAVES
    The answer would appear to lie in the process of fast Alfvén mode conversion

    http://iopscience.iop.org/article/10.3847/0004-637X/817/1/45/meta#apj522109s5
    (2016 study)

  9. pochas94 says:

    @oldbrew,

    Thanks

  10. Jim says:

    Interesting arguements. But, leave a lot open, yet. Energy states, 0 and 1, I don’t buy that one. Not all is binary. Only with applied filters can we view what is happening on the sun.those filters show us what happens within that range. Limiting all other ranges to nothing. What else is there going on at the same time, in that area. Where are the waves initiating from, what controls them, and …
    Agreed, they could help us understand, but camera filters are like preconcieved notions, incomplete.

  11. dscott says:

    So what they are really saying is that the Sun is being heated like a hob, via induction. Which means the magnetic field is oscillating at a frequency that will heat Hydrogen and Helium.

    http://www.explainthatstuff.com/induction-cooktops.html

  12. oldbrew says:

    dscott – to get that hob to work needs an electricity supply, and then there’s a magnetic field.

    When we turn to the Sun, we find magnetism…

  13. oldbrew says:

    Axios: Jupiter is nothing like scientists expected

    “In almost every field, our ideas of what Jupiter was like are largely incorrect.”
    — Scott Bolton, Principal Investigator of NASA’s Juno mission

    Key findings from the four studies published in Nature today:

    — The planet’s gravitational field varies in the northern and southern hemispheres. That’s surprising because the fast-rotating gas planet was expected to generate a uniform gravitational effect.

    — The strange field arises because the winds at the surface extend deep — about 3,000 kilometers — into the planet, another team reported. Jupiter’s bands therefore run deep. The source of the winds is unknown.

    — Jupiter’s gaseous core — mostly made of helium and hydrogen — seems to rotate as a solid body.

    — Unlike Saturn’s single storms, there are patterned clusters of cyclones at Jupiter’s poles. How they form and remain stable is a puzzle.

    http://www.axios.com/jupiters-interior-isnt-what-scientists-thought-204c06b1-77c2-4c1e-ad5c-1c70f924155e.html
    – – –
    Re. ‘Jupiter’s gaseous core — mostly made of helium and hydrogen’

    Has that been directly observed – or is it what they think they know?

  14. oldbrew says:

    Three NASA satellites recreate solar eruption in 3-D
    March 9, 2018 by Lina Tran, NASA’s Goddard Space Flight Center

    Read more at: http://phys.org/news/2018-03-nasa-satellites-recreate-solar-eruption.html

    This movie [25 seconds] illustrates the recreation of a CME and shock that erupted from the Sun on March 7, 2011. The pink lines show the CME structure and the yellow lines show the structure of the shock – a side effect of the CME that can spark space weather events around Earth. Credit: NASA’s Goddard Space Flight Center/GMU/APL/Joy Ng

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