New mechanism proposed that describes all solar eruptions

From NASA/GODDARD SPACE FLIGHT CENTER and the “solar eruptions are still a bigger threat to humanity than global warming” department.

Scientists propose mechanism to describe solar eruptions of all sizes

Banner image: A long filament erupted on the sun on Aug. 31, 2012, shown here in imagery captured by NASA’s Solar Dynamics Observatory. CREDIT NASA’s Goddard Space Flight Center/SDO

From long, tapered jets to massive explosions of solar material and energy, eruptions on the sun come in many shapes and sizes. Since they erupt at such vastly different scales, jets and the massive clouds — called coronal mass ejections, or CMEs — were previously thought to be driven by different processes.

Scientists from Durham University in the United Kingdom and NASA now propose that a universal mechanism can explain the whole spectrum of solar eruptions. They used 3-D computer simulations to demonstrate that a variety of eruptions can theoretically be thought of as the same kind of event, only in different sizes and manifested in different ways. Their work is summarized in a paper published in Nature on April 26, 2017.

The study was motivated by high-resolution observations of filaments from NASA’s Solar Dynamics Observatory, or SDO, and the joint Japan Aerospace Exploration Agency/NASA Hinode satellite. Filaments are dark, serpentine structures that are suspended above the sun’s surface and consist of dense, cold solar material. The onset of CME eruptions had long been known to be associated with filaments, but improved observations have recently shown that jets have similar filament-like structures before eruption too. So the scientists set out to see if they could get their computer simulations to link filaments to jet eruptions as well.

“In CMEs, filaments are large, and when they become unstable, they erupt,” said Peter Wyper, a solar physicist at Durham University and the lead author of the study. “Recent observations have shown the same thing may be happening in smaller events such as coronal jets. Our theoretical model shows the jet can essentially be described as a mini-CME.”

Solar scientists can use computer models like this to help round out their understanding of the observations they see through space telescopes. The models can be used to test different theories, essentially creating simulated experiments that cannot, of course, be performed on an actual star in real life.

The scientists call their proposed mechanism for how these filaments lead to eruptions the breakout model, for the way the stressed filament pushes relentlessly at — and ultimately breaks through — its magnetic restraints into space. They previously used this model to describe CMEs; in this study, the scientists adapted the model to smaller events and were able to reproduce jets in the computer simulations that match the SDO and Hinode observations. Such simulations provide additional confirmation to support the observations that first suggested coronal jets and CMEs are caused in the same way.

“The breakout model unifies our picture of what’s going on at the sun,” said Richard DeVore, a co-author of the study and solar physicist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “Within a unified context, we can advance understanding of how these eruptions are started, how to predict them and how to better understand their consequences.”

The key for understanding a solar eruption, according to Wyper, is recognizing how the filament system loses equilibrium, which triggers eruption. In the breakout model, the culprit is magnetic reconnection — a process in which magnetic field lines come together and explosively realign into a new configuration.

In stable conditions, loops of magnetic field lines hold the filament down and suppress eruption. But the filament naturally wants to expand outward, which stresses its magnetic surroundings over time and eventually initiates magnetic reconnection. The process explosively releases the energy stored in the filament, which breaks out from the sun’s surface and is ejected into space.

Exactly which kind of eruption occurs depends on the initial strength and configuration of the magnetic field lines containing the filament. In a CME, field lines form closed loops completely surrounding the filament, so a bubble-shaped cloud ultimately bursts from the sun. In jets, nearby fields lines stream freely from the surface into interplanetary space, so solar material from the filament flows out along those reconnected lines away from the sun.

“Now we have the possibility to explain a continuum of eruptions through the same process,” Wyper said. “With this mechanism, we can understand the similarities between small jets and massive CMEs, and infer eruptions anywhere in between.”

Confirming this theoretical mechanism will require high-resolution observations of the magnetic field and plasma flows in the solar atmosphere, especially around the sun’s poles where many jets originate — and that’s data that currently are not available. For now, scientists look to upcoming missions such as NASA’s Solar Probe Plus and the joint ESA (European Space Agency)/NASA Solar Orbiter, which will acquire novel measurements of the sun’s atmosphere and magnetic fields emanating from solar eruptions.

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32 thoughts on “New mechanism proposed that describes all solar eruptions

  1. Confirming this theoretical mechanism will require high-resolution observations of the magnetic field and plasma flows in the solar atmosphere, especially around the sun’s poles where many jets originate — and that’s data that currently are not available.

    So … they have made a prediction that can be tested. That’s way better than the climate science we are usually subjected to.

  2. Money quote:

    “Confirming this theoretical mechanism will require high-resolution observations of the magnetic field and plasma flows in the solar atmosphere, especially around the sun’s poles where many jets originate — and that’s data that currently are not available. ”

    The model may eventually agrees with those observations (how CMEs form and erupt), but the unstable (non-linear) dynamics means forecasting a real CME’s magnitude and release timing will remain unlikely. Fortunately, at 150 Million km we have some time to see the big Carrington-like ones coming (18-24 hrs for the biggees).

    Sort of like trying to forecast a specific stroke of lightning from a storm. We can be certain that particular weather conditions will be favorable for a storm with lots of lightning, but saying there will be a stroke at “this place-time” and of “this strength” is foolish. It becomes stochastic event, not a determinate event.

    • joelobryan April 28, 2017 at 10:01 am
      ..Sort of like trying to forecast a specific stroke of lightning from a storm. We can be certain that particular weather conditions will be favorable for a storm with lots of lightning, but saying there will be a stroke at “this place-time” and of “this strength” is foolish. It becomes stochastic event, not a determinate event…

      Be optimistic Joel.
      For instance, let’s say there are 6 sunspots on the sun. Number 5 has been growing and is now on its second rotation and Earth facing again. Indications are the field topology and filaments are more unstable then the last rotation. Based on size and location we get an estimated impact magnitude and arrival time notice. We already do this. Was it an unseen wave that finally destabilizes the sunspot or its size based on angle and location?

  3. This is a good example of the hype associated with almost any research. “unprecedented”, “never seen before”, “new insight”, etc.
    This mechanism is not new. It has long been thought to be the mechanism underlying all explosive releases of pent-up magnetic energy.
    Perhaps what is new is that is shuts up some doubters of reconnection, although I doubt they will be convinced.

    • Thanks, Leif, always good to get my suspicions confirmed by someone who actually knows. I stopped reading when they said oh, we don’t have the data to test this brilliant idea, but by gosh we sure think it’s true …

      w.

    • Dr. S.
      Can you shed any light on the Solar Orbiter and Solar Probe missions mentioned in the article:
      “Confirming this theoretical mechanism will require high-resolution observations of the magnetic field and plasma flows in the solar atmosphere, especially around the sun’s poles where many jets originate — and that’s data that currently are not available. For now, scientists look to upcoming missions such as NASA’s Solar Probe Plus and the joint ESA (European Space Agency)/NASA Solar Orbiter, which will acquire novel measurements of the sun’s atmosphere and magnetic fields emanating from solar eruptions.”

      My understanding is there has only been one mission that had a polar orbit, the Ulysses spacecraft that completed 2 elliptical orbits through the southern polar region.

      Question: Do any space probes have instruments to measure electrical fields to complement the magnetic field measurements?

    • Leif “explosive releases of pent-up magnetic energy”

      Explosive releases of pent-up electrically charged magnetic energy . When will you concede that’ without electricity, gravity and magnetism would not exist?

      “Electromagnetism, science of charge and of the forces and fields associated with charge. Electricity and magnetism are two aspects of electromagnetism.

      Electricity and magnetism were long thought to be separate forces. It was not until the 19th century that they were finally treated as interrelated phenomena.”
      https://www.britannica.com/science/electromagnetism

    • Possibly more appropriately tensor calculus, but an interesting point of view though the abstraction supposes to describe a physical phenomenon.

      • I’m confused. Maxwell’s Equations can be bundled up into a tensor if one chooses, but the discussion here is about magnetic field lines, so do not three dimensional vectors suffice?

  4. Quote: Their work is summarized in a paper published in Nature on April 26, 2017.

    I wonder how long it will be before scientists wanting to protect their reputations stop publishing in Science and Nature.

  5. So they made a model match observations. hmmm, reminds me of something.

    Surely you model then observe to see if the model is working, isn’t that how it works, otherwise you end up with cargo cult science.

  6. and of course this is in no way related to thermonuclear solar model. Another add-on. The sun is a patchwork of unconnected theories. We are still mostly “in the dark” on Sol truth be told.

  7. Anyone else notice the top picture looks like the sun is birthing a plasma armadillo?
    It’s a miracle, I tells ya! :-)

  8. “In jets, nearby fields lines stream freely from the surface into interplanetary space, so solar material from the filament flows out along those reconnected lines away from the sun.”

    Huh? Since when do magnetic “field lines” stream freely into space. Gauss would demur.

    • Many here seem to be having this problem. It must be remembered that the magnetic fields are created by and trapped in the plasma, which in turn affects the plasma.

  9. Robert hits my issue. This concept of gravity being a linear structure, starting at point A and extending in a narrow line to a termination point out in space just don’t smell right. Almost like saying gravity is a rope extending out from an object instead of a blanket covering it.

    As for the mechanism which creates CMEs, flares and ropes, as they say, we need more observation. Hinode, STEREO, SDO, IRIS are all excellent tools, they just need to be used longer and others added. Time will expand our knowledge, speculating with insufficient data and flawed models is just what happens till the fund of concrete knowledge produces the answers.

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