Researchers simulate how 'coherent structures' affect solar wind heating

March 26, 2018, Centrum Wiskunde & Informatica
The March PRL cover showcases the research. Credit: Physical Review Letters

Researchers from Centrum Wiskunde & Informatica (CWI), the national research institute for mathematics and computer science in the Netherlands, have studied how solar wind particles are accelerated and heated. In particular, they discovered how coherent structures in the solar wind, where the magnetic fields and electrical currents are enhanced, affect the energy transfer responsible for heating. The results were published in Physical Review Letters on 19 March 2018.

The sun emits a constant stream of charged particles, which form the so-called . At some distance from the sun, the solar wind is hotter than expected, which means some process is still heating the particles even after they leave the solar atmosphere. One of the outstanding questions in space physics is where and how this heating takes place. The longstanding hypothesis is that the sun causes turbulence in the emitted solar wind. That turbulence stirs the solar wind, and thus further accelerates and heats the particles.

In many turbulent flows, large-scale motions (big whirls) affect small-scale motions (little whirls). That means there is an between motions on different scales. This is also the case in the turbulent solar wind. However, in solar wind, the way in which the energy transfer happens, turns out to be surprising. The researchers found that the energy transfer is very inhomogeneous: it happens only in specific locations. In fact, 80 percent of the energy transfer happens in about 50 percent of the space.

In a paper published in Physical Review Letters, CWI researcher Enrico Camporeale, together with colleagues from Italy and France, addresses why this is the case. They found that certain structures in the solar wind, where the and the electrical currents are enhanced, are responsible for the inhomogeneity. These structures naturally emerge in all turbulent low density plasma's, of which solar is an example. They are typically in the form of elongated sheets where the magnetic field and the electrical currents are higher than elsewhere.

The work leads to a better understanding of the plasma turbulence in solar winds. A deep understanding of this phenomenon is necessary to develop better forecasts of harmful solar events, such as energetic that can damage satellites and electrical power grids.

To reach their conclusion, the team used high-resolution simulations, run at the Italian supercomputer center CINECAB. By using an innovative space-filter technique, they have been able to calculate the amount of energy transfer from large to small scales in different regions of the simulation, and to quantify the importance of coherent structures.

Explore further: Cluster measures turbulence in Earth's magnetic environment

More information: E. Camporeale et al. Coherent Structures and Spectral Energy Transfer in Turbulent Plasma: A Space-Filter Approach, Physical Review Letters (2018). DOI: 10.1103/PhysRevLett.120.125101

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16 comments

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RealityCheck
1 / 5 (5) Mar 26, 2018
@jonesdave, @Da Schneib, @cantdrive85.

Just to further inform your mutual discussion/arguments re the Solar Wind, here is a PO article (above) indicating that the SW has electric currents, and electric/magnetic fields etc which arise and evolve etc over specifically applicable timescales (as I have been long pointing out) in ALL 'plasma flow with FAST electrons' situations everywhere, at all scales from lab to astro/cosmic.

So please 'adjust your beliefs' accordingly before continuing your mutual discussion re SW and other (simplistically) so-called "collisionless plasma" flows contexts/phenomena.

Good luck and good thinking all. :)

cantdrive85
1 / 5 (4) Mar 26, 2018
In particular, they discovered how coherent structures in the solar wind, where the magnetic fields and electrical currents are enhanced, affect the energy transfer responsible for heating.

jonesdumb? ROTFLMAO!
Coherent structures! Such as Birkeland currents and double layers.
However, in solar wind, the way in which the energy transfer happens, turns out to be surprising. The researchers found that the energy transfer is very inhomogeneous: it happens only in specific locations. In fact, 80 percent of the energy transfer happens in about 50 percent of the space

Electric discharge explains how this is at specific locations.
These structures naturally emerge in all turbulent low density plasma's, of which solar wind is an example. They are typically in the form of elongated sheets where the magnetic field and the electrical currents are higher than elsewhere.

Double layers.
Frozen-in is dead!
cantdrive85
1 / 5 (4) Mar 26, 2018
Even more realistic MHD shows what has been said for years, the simplistic plasmas jonesdumb relies upon for his beliefs don't exist in reality. Alfven is proving to be right again as these space plasmas looks more and more like laboratory plasmas with every improved resolution. The physics of plasmas are primarily electric discharge phenomena.
cantdrive85
1 / 5 (4) Mar 26, 2018
It cannot be underestimated the significance of how energy is transferred in plasmas and how it relates to space weather, Earth's climate, and geology among numerous other phenomena. Quite frankly, it is the primary reason I am skeptical of AGW (although the politicization is a close second), there is no real understanding of the Earth-Sun connection and how the energy transfer operates. It's based on simplistic maths based models which have no basis in reality.
jonesdave
5 / 5 (4) Mar 26, 2018
Even more realistic MHD shows what has been said for years, the simplistic plasmas jonesdumb relies upon for his beliefs don't exist in reality. Alfven is proving to be right again as these space plasmas looks more and more like laboratory plasmas with every improved resolution. The physics of plasmas are primarily electric discharge phenomena.


Jesus H. Christ! Alfven, if you are right, has been proved to be wrong! He modelled his comet - solar wind interaction using the frozen-in approximation. And was still saying it was fine to use 30 years later. This finding is nothing new. Merely the model. The effect only occurs in turbulent conditions. Guess what one of the phenomena they are proposing for these small-scale short-lived events is? Magnetic reconnection! The turbulence dissipates with distance. It has been known about since before Alfven's 1987 table, where he tells us it is fine to use the frozen-in concept in certain conditions.
cantdrive85
1 / 5 (3) Mar 27, 2018
Wow, everyday you prove to be stupider than the previous day. Read his Nobel lecture, read the paper 'On frozen‐in field lines and field‐line reconnection'
From 1976, entire abstract;

Abstract
It is shown that 'frozen‐in magnetic field lines' and 'magnetic field‐line reconnection' are unnecessary and often misleading concepts.

Obviously it is misleading you. He gave up on frozen-in fields and MHD prior to his Nobel was awarded.
jonesdave
5 / 5 (4) Mar 27, 2018
Wow, everyday you prove to be stupider than the previous day. Read his Nobel lecture, read the paper 'On frozen‐in field lines and field‐line reconnection'
From 1976, entire abstract;

Abstract
It is shown that 'frozen‐in magnetic field lines' and 'magnetic field‐line reconnection' are unnecessary and often misleading concepts.

Obviously it is misleading you. He gave up on frozen-in fields and MHD prior to his Nobel was awarded.


In which case he's a fraud for accepting it, and deserves no further attention. Particularly when he then lies in a 1987 paper, and says that the frozen-in condition is fine to use in some circumstances. See Table 1.
cantdrive85
1 / 5 (4) Mar 27, 2018
No, it's what made him a scientist, when it was wrong he moved on. He had an idea in the 30's (frozen-in fields), he realized he was wrong but couldn't figure out why. Then with Falthammar in '60's figured out why. He told about it in his Nobel lecture, wrote a couple papers, and warned how carefully it should be used. You obviously didn't listen or understand.
When the data became more robust, he adjusted his views. It's called progress and if he saw the most recent data he may have disavowed it completely.
jonesdave
4.2 / 5 (5) Mar 27, 2018
No, it's what made him a scientist, when it was wrong he moved on. He had an idea in the 30's (frozen-in fields), he realized he was wrong but couldn't figure out why. Then with Falthammar in '60's figured out why. He told about it in his Nobel lecture, wrote a couple papers, and warned how carefully it should be used. You obviously didn't listen or understand.
When the data became more robust, he adjusted his views. It's called progress and if he saw the most recent data he may have disavowed it completely.


So why was he still advocating it in 1987?
Da Schneib
5 / 5 (1) Mar 27, 2018
Hmmm, looks like this is chaos theory.

BTW worth noting that no one ever said there aren't local currents in the solar wind. Just that there's no consistent current across the whole of the solar wind. This is obvious electrodynamics since for the Sun to emit a consistent current would result in it acquiring a charge, which it does not have. An object can't after all go on emitting protons or electrons by themselves forever without acquiring a charge. That's basic. And BTW if that had been going on for billions of years then the planets would all have gotten the opposite charge by absorbing solar wind particles, and would all fall into the Sun.

We'll call that the Solar Catastrophe of the Thunderdolts.
cantdrive85
1 / 5 (3) Mar 27, 2018
So why was he still advocating it in 1987?

He explained over and over again how carefully it be applied, you and many others did not heed the warning.
The effect only occurs in turbulent conditions.

Right, like the article explained;
"The longstanding hypothesis is that the sun causes turbulence in the emitted solar wind."
And
"They found that certain structures in the solar wind, where the magnetic field and the electrical currents are enhanced, are responsible for the inhomogeneity. These structures naturally emerge in all turbulent low density plasma's, of which solar wind is an example."

LOL, low density turbulent plasmas, of which the solar wind is an example...
cantdrive85
1 / 5 (3) Mar 27, 2018
BTW worth noting that no one ever said there aren't local currents in the solar wind.

That is exactly what jonesdumb is saying.
This is obvious electrodynamics since for the Sun to emit a consistent current would result in it acquiring a charge

Which it has...
An object can't after all go on emitting protons or electrons by themselves forever without acquiring a charge.

The Sun is part of a larger circuit, "by themselves" is not relevant.
jonesdave
5 / 5 (2) Mar 27, 2018
He explained over and over again how carefully it be applied, you and many others did not heed the warning.


And in 1987 was still advocating its use in the interaction between the solar wind and comets. And elsewhere. In Table 1. In black & white. And explained it in the text of the paper. In black & white. So, I'm afraid you're lying again. As can be (and has been) easily shown.
And plasma physicists these days know a hell of a lot more about the plasmas in the environments Alfven was interested in than he ever did.
jonesdave
5 / 5 (1) Mar 27, 2018
So why was he still advocating it in 1987?

He explained over and over again how carefully it be applied, you and many others did not heed the warning.
The effect only occurs in turbulent conditions.

Right, like the article explained;
"The longstanding hypothesis is that the sun causes turbulence in the emitted solar wind."
And
"They found that certain structures in the solar wind, where the magnetic field and the electrical currents are enhanced, are responsible for the inhomogeneity. These structures naturally emerge in all turbulent low density plasma's, of which solar wind is an example."

LOL, low density turbulent plasmas, of which the solar wind is an example...


From a non-plasma physicist, who belongs to a cult that believe Earth used to orbit Saturn! Do one, mate. There is nobody within your cult with the faintest clue about plasma physics. Is there, woo boy?
cantdrive85
1 / 5 (3) Mar 27, 2018
And in 1987 was still advocating its use in the interaction between the solar wind and comets

To model it, but in light of that he insisted it not be misconstrued that the field lines are actually frozen-in to the plasma. This is why he said it was a dangerous pseudo-pedagogical concept, because morons like you cannot grasp the implicit complexity therein. He didn't rail against the frozen-in concept for 20+-years because he thought it was a great conceptual tool.
RealityCheck
1 / 5 (3) Mar 27, 2018
@jonesdave, @Da Schneib, @cantdrive85.

Two observations for your discussion:

1) The 'relic' Magnetic field would 'decay' over time/space if it propagates from a 'source' that is no longer generating it; JUST AS a 'relic' Gravitational field of the Moon would 'decay' over time/space if the Moon 'generating' that field were to 'disappear' in a (purely to illustrate point) total matter-antimatter annihilation event 'lost' Moon's mass-energy via gamma-rays away from its former location).

2) Newton's simplistic maths is 'good enough' for rough calcs/models BUT Einsteinian Relativity is required for better representation/calculation of the effects in higher mass/energy phenomena contexts; LIKEWISE, Alfven's (old) 'frozen-in mag fields' understandings/treatment is OK for rough calcs/models BUT must be replaced by (newer) understandings/treatments which must include FAST-electron behaviour/currents etc to properly model the more complex phenomena 'system as a whole'.

Cheers. :)

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