Plasma bubbles help trigger massive magnetic events in outer space

March 2, 2018, US Department of Energy
PPPL physicist Yi-Min Huang. Credit: Elle Starkman

Scientists at the U.S. Department of Energy's (DOE) Princeton Plasma Physics Laboratory (PPPL) have discovered key conditions that give rise to fast magnetic reconnection, the process that triggers solar flares, auroras, and geomagnetic storms that can disrupt signal transmissions and other electrical activities, including cell phone service. The process occurs when the magnetic field lines in plasma, the hot, charged state of matter composed of free electrons and atomic nuclei, break apart and violently reconnect, releasing vast amounts of energy. This happens in thin sheets of plasma, called current sheets, in which electric current is strongly concentrated.

By incorporating computer simulations, the findings add to an earlier theory of fast reconnection developed mathematically by physicists at PPPL and Princeton University. The new results incorporate a predictive model that gives a more complete description of the physics involved.

The impact of reconnection can be felt throughout the universe. The process may cause enormous bursts of gamma-ray radiation thought to be associated with supernova explosions and the formation of ultra-dense neutron stars and black holes. "A gamma-ray burst in our Milky Way galaxy, if pointing towards Earth, could potentially cause a ," said PPPL physicist Yi-Min Huang, lead author of a paper reporting the findings in Astrophysical Journal. "Clearly, it is important to know when, how, and why magnetic reconnection takes place."

Scientists have observed that reconnection happens suddenly, after a long period of quiescent behavior by magnetic fields inside current sheets. What exactly causes the magnetic fields to separate and reconnect, and why does the reconnection take place more quickly than theory says it should?

Using computer simulations and theoretical analysis, the physicists demonstrated that a phenomenon called the "plasmoid instability" creates bubbles within that can lead to reconnection when certain conditions are met:

  • The plasma must have a high Lundquist number, which characterizes how well it conducts electricity.
  • Random fluctuations in the of the plasma provide "seeds" from which the grows.

Taken together, these conditions allow plasmoid instabilities to give rise to reconnection in current sheets. "Our study suggests that disruption of the current caused by the plasmoid instability may provide a trigger," Huang said.

The trigger breaks up two-dimensional sheets of electric current within plasma into bubbles, or plasmoids, and many smaller sheets. The growing number of sheets creates more opportunity for magnetic lines to break apart and join together. Reconnection also occurs in more than one place, causing the aggregate rate for an entire system to increase.

The smaller size of current sheets speeds up reconnection as well. Electromagnetic forces tend to propel the plasma between sheets, producing motion that accelerates when the sheets break into smaller ones. The accelerating plasma brings magnetic lines together more quickly and leads to faster reconnection rates.

Huang and fellow physicists would like to test their new model using experimental machines with additional capability. While no such machine exists at present, researchers look forward to a new unit that is coming online.

Explore further: Researchers propose an explanation for the mysterious onset of a universal process

More information: Yi-Min Huang et al. Plasmoid Instability in Evolving Current Sheets and Onset of Fast Reconnection, The Astrophysical Journal (2017). DOI: 10.3847/1538-4357/aa906d

Related Stories

Team produces unique simulation of magnetic reconnection

September 8, 2017

Jonathan Ng, a Princeton University graduate student at the U.S. Department of Energy's (DOE) Princeton Plasma Physics Laboratory (PPPL), has for the first time applied a fluid simulation to the space plasma process behind ...

Recommended for you

Scientists produce 3-D chemical maps of single bacteria

November 16, 2018

Scientists at the National Synchrotron Light Source II (NSLS-II)—a U.S. Department of Energy (DOE) Office of Science User Facility at DOE's Brookhaven National Laboratory—have used ultrabright x-rays to image single bacteria ...

Bursting bubbles launch bacteria from water to air

November 15, 2018

Wherever there's water, there's bound to be bubbles floating at the surface. From standing puddles, lakes, and streams, to swimming pools, hot tubs, public fountains, and toilets, bubbles are ubiquitous, indoors and out.

Terahertz laser pulses amplify optical phonons in solids

November 15, 2018

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg/Germany presents evidence of the amplification of optical phonons ...

Quantum science turns social

November 15, 2018

Researchers in a lab at Aarhus University have developed a versatile remote gaming interface that allowed external experts as well as hundreds of citizen scientists all over the world to optimize a quantum gas experiment ...

19 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

cantdrive85
1.4 / 5 (9) Mar 02, 2018
Pseudoscience to the left, plasma "bubbles" to the right, and real science in the middle when the electric circuitry and electric currents are considered.
https://www.ann-g...65/2017/
No matter to the degree the plasma ignoramuses want to conjure up magnetic monopoles to round out their pseudoscientific claptrap TOE, reality will not allow it.
By relying on the plasmoid to explain the explosive events the plasma ignoramuses are coming back to the realization that Alfven and his exploding circuit was correct all along.
691Boat
5 / 5 (4) Mar 02, 2018
@CD85:
What happens to the magnetic field of an "exploding circuit" if the break in the circuit stops current flow?
cantdrive85
1 / 5 (5) Mar 03, 2018
The magnetic field collapses and much of the inductive energy in the circuit is released explosively. Once the current resumes new magnetic fields are created. No pseudoscience required, no moving, breaking, or reconnecting occurs.

Field "A" experiences an instability, the instability interrupts the currents driving the circuit, the inherently explosive circuit releases it energy.
There is still energy and matter present, the electric currents "reconnect" to create a new circuit which in turn results in a new field "B".
There is no magnetic reconnection, the magnetic fields are a result of the electric currents/circuits.
It would seem the above researchers found just that, as I have been explaining for quite sometime now.
jonesdave
2.3 / 5 (6) Mar 03, 2018
There is still energy and matter present, the electric currents "reconnect" to create a new circuit which in turn results in a new field "B".


Well, that ain't what the paper is saying, so I'm guessing you just made that up. By the way, they used a MHD simulation to get the results!
cantdrive85
1 / 5 (3) Mar 03, 2018
By the way, they used a MHD simulation to get the results!

Curious, isn't it? Especially since you keep claiming that any plasma physicist researching MRx "knows" MHD is violated in the process. It is also likely the reason why they didn't report on the double layers that must be present when there are current sheets and plasmoids involved. MHD models cannot resolve such parts of the circuit.
jonesdave
2.7 / 5 (7) Mar 03, 2018
By the way, they used a MHD simulation to get the results!

Curious, isn't it? Especially since you keep claiming that any plasma physicist researching MRx "knows" MHD is violated in the process. It is also likely the reason why they didn't report on the double layers that must be present when there are current sheets and plasmoids involved. MHD models cannot resolve such parts of the circuit.


Nope. Once again, that is just your inability to understand plasma physics, and the jargon therein. I don't claim to be an expert, but even I know that resistive MHD is not ideal MHD, or Hall MHD. The frozen-in condition is broken by R-MHD. If you looked at any of Falthammars references, when he mentions MRx, you'll see those authors using such models.
You need to forget about the 1960s and 70s, and Alfven's objections, because he was talking about people using ideal MHD to model MRx, which you cannot do. And nobody does.
jonesdave
2.7 / 5 (7) Mar 03, 2018
MHD models cannot resolve such parts of the circuit.


Why would they need to? They can, and do, perform experiments in the lab, which the PPPL people have been doing for two decades. You can watch reconnection in action. No DLs are formed. Falty would tell you that, even though he still bangs on about them elsewhere.
cantdrive85
2 / 5 (4) Mar 03, 2018
Explain then, how exactly do you form a "plasma bubble" without a surface feature to separate it from the surrounding plasma? How would you identify it as a "bubble"?
cantdrive85
2 / 5 (4) Mar 03, 2018
I don't claim to be an expert, but even I know that resistive MHD is not ideal MHD, or Hall MHD.

Well, that's remarkably obvious. Anyways, as Akasofu's paper points out, the MHD models don't resolve where the energy comes from, in those models "it's just there". Recall, you need a dynamo, transport, as well as the dissipation. And you most certainly need a circuit.
jonesdave
2.7 / 5 (7) Mar 03, 2018
Explain then, how exactly do you form a "plasma bubble" without a surface feature to separate it from the surrounding plasma? How would you identify it as a "bubble"?


Why do I need to explain it? I'm not a plasma physicist, and neither are you. However, I would take a look at this paper:

Anomalous Heating and Plasmoid Formation in a Driven Magnetic Reconnection Experiment
Hare, J. D. et al.
https://arxiv.org...9234.pdf

As Hare et al say:

The plasmoid instability breaks the current sheet into numerous smaller sheets; in MHD, this is known to enable the rapid and efficient conversion of magnetic energy to thermal and kinetic energy.


Which is what Huang is saying.
jonesdave
2.7 / 5 (7) Mar 03, 2018
By the way, the paper linked in the article above is behind a paywall. However, there is a pre-print here:

PLASMOID INSTABILITY IN EVOLVING CURRENT SHEETS AND ONSET OF FAST RECONNECTION
Huang, Y-M. et al.
https://arxiv.org...1863.pdf
jonesdave
3 / 5 (8) Mar 03, 2018
Ooooh, this is cool! Here is Hale et al's plasmoids in a gif movie:
https://drive.goo...dWM/view
rrwillsj
2.3 / 5 (3) Mar 04, 2018
cantdrive85, I gotta admit you have thoroughly confused me! Thank you?

Perhaps it is the limits of my comprehension but it seems to me that you are claiming that the conclusions and speculations in this article, based on the technologies of sciences you reject? Somehow prove your conjectures to be correct? Without any empirical evidence to back up your claims.

Furthermore, either all these scientists are co-conspirators in a vast cosmic plot to suppress the grandeur of your sibylline wisdom?

Or, they are busy accomplishing real work and just ignoring your pesky buzzing?

Either you are pregnant or you are not pregnant. Unless you are set of conjoined hermaphrodites?
granville583762
4 / 5 (4) Mar 05, 2018
Magnetic toroidal currants (plasmoids)
Magnetic toroidal regions of circular magnetic fields. Torus entities that are attracting, repelling, combining and looping. In fact they are simply a currant rotating in a large circle encircled at right angles by its electric field, exactly as a continuous circular currant carrying conductor where Flemings rule dictates the direction of field where the conductor is toroidal plasma! The magnetic field compress's the toroidal plasma such that it reaches the critical point of fusion, a lesson fusion reactor manufacturers seem to be lacking.
granville583762
4 / 5 (4) Mar 05, 2018
A single loop of magnetic field
These plasmatic toroidal currants put paid to magnetic monopoles as the magnetic fields are expanding in continuous concentric loops, taking a single continuous magnetic loop is a single magnetic field which is as close as anyone can get to a magnetic monopole, but a moments inspection shows the currant in the plasma closes the loop allowing plasma and currant to flow continuously where two single magnetic fields diametrically appose each other which turns the doughnut into a equivalent of a solenoid. The magnetic field is circular loop and cannot be broken into isolated monopoles because it is exactly the same identical field encircling the electron.
granville583762
4 / 5 (4) Mar 05, 2018
For the electron to have a dipole moment requires two diametrically opposed magnetic fields to create a magnetic moment which is two electrons circling (orbiting) each other creating a currant loop and consequently a magnetic moment or a single electron spinning its magnetic field such that in 180degrees it is effectively in diametrical opposition creating a magnetic dipole moment effectively the single electron is forming a currant loop exactly as flows in a single circular conductor and plasma.
granville583762
4 / 5 (4) Mar 05, 2018
For the electron to have a dipole moment requires two diametrically opposed magnetic fields to create a magnetic moment which is two electrons circling (orbiting) each other creating a currant loop and consequently a magnetic moment or a single electron spinning its magnetic field such that in 180degrees it is effectively in diametrical opposition creating a magnetic dipole moment effectively the single electron is forming a currant loop exactly as flows in a single circular conductor and plasma.

The electrons spin axis is not in line with the spin axis of the magnetic field essentially the field is wobbling in diametrical opposition creating a dipole moment.
andyf
4.3 / 5 (3) Mar 05, 2018
Currants are dried seedless grapes.

0/10 - must try harder.
granville583762
4 / 5 (4) Mar 07, 2018
Yes i know, they go well in scones with butter and jam!
Currants are dried seedless grapes.

0/10 - must try harder.


Don't take my word for it, do some number crunching, you will be surprised what find!

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.