Engineers create stable plasma ring in open air

Engineers create stable plasma ring in open air
A torus of plasma, viewed from above. The ring is created by a jet of water striking a crystal plate. Credit: Mory Gharib/Caltech

For the first time, engineers at Caltech have created a stable ring of plasma in open air—essentially capturing lightning in a bottle, but without the bottle.

Matter can exist in four distinct phases: solid, liquid, gas, and . Plasmas are made of charged particles—ions and electrons—and occur naturally on Earth as lightning, in the weather phenomenon called St. Elmo's fire (in which glowing balls of light sometimes appear on pointed objects during storms), and in man-made objects such as and plasma cutting torches.

Usually, plasmas do not have clearly defined shapes of their own. Lightning follows a path of least resistance through the air, creating wildly forking structures, while man-made plasmas are constrained by vacuum chambers or electromagnetic fields.

As such, Morteza (Mory) Gharib (PhD '83), the Hans W. Liepmann Professor of Aeronautics and Bioinspired Engineering at Caltech, says he was surprised when he and his team were able to generate a stable ring of plasma in open air using just a stream of and a crystal plate. Their findings will be published in the Proceedings of the National Academy of Sciences the week of November 13.

Stable plasma torus. Credit: Caltech
"We were told by some colleagues this wasn't even possible. But we can create a stable ring and maintain it for as long as we want, no vacuum or magnetic field or anything," says co-author Francisco Pereira of the Marine Technology Research Institute in Italy, a visiting scholar at Caltech.

The stream of water is an 85-micron-diameter jet blasting from a specially designed nozzle at 9,000 pounds per square inch that strikes the crystal plate with an impact velocity of around 1,000 feet per second. For reference, that's a stream narrower than a human hair moving about as fast as a bullet fired from a handgun.

In their study, Gharib and his team experimented with both crystal plates of quartz and lithium niobate, each of which can induce the triboelectric effect—in which an electric charge builds up because of friction with another material. When the jet hits the crystal, the water creates a smooth, laminar flow of positively charged ions across the negatively charged surface. At the shear region, where the stream strikes the surface and flows outward across it, the triboelectric effect triggers a high flow of electrons through the water to its surface. This flow of electrons ionizes the atoms and molecules in the surrounding gas near the surface of the water, creating a donut, or torus, of glowing plasma that is dozens of microns in diameter and visible under a microscope.

Gharib and his team fired the water jet at surfaces of different textures and found that the smoother the surface, the clearer the structure of the plasma ring. The ring is stable, and as long as the water continues to flow, the ring maintains its shape and size.

Engineers create stable plasma ring in open air
The illustration depicts how the ring is created, in profile. At the shear region, the flow of water induces the triboelectric effect in the crystal, building an electrical charge that flows through the water to its surface. Credit: Mory Gharib/Caltech

In addition, engineers working with the plasma noticed that their cell phones encountered high levels of radio frequency noise—static—while they were in the same room as the experiment. It turns out that the plasma ring emits distinct radio frequencies. "That's never been seen before. We think it's because of the piezo properties of the materials that we used in our experiments," Pereira says, referring to the materials' ability to be electrically polarized through mechanical stress—in this case, the flowing of water.

Gharib has applied for a patent on the torus-generating technique. Though it does not have any immediate commercial applications, the ability to generate a stable of plasma without powerful or vacuum suggests the possible use of plasma structures to store energy, Gharib says.

The paper is titled "Toroidal plasmoid generation via extreme hydrodynamic shear."


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More information: Morteza Gharib el al., "Toroidal plasmoid generation via extreme hydrodynamic shear," PNAS (2017). www.pnas.org/cgi/doi/10.1073/pnas.1712717114
Citation: Engineers create stable plasma ring in open air (2017, November 15) retrieved 27 May 2019 from https://phys.org/news/2017-11-stable-plasma-air.html
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Nov 15, 2017
"We were told by some colleagues this wasn't even possible. But we can create a stable ring and maintain it for as long as we want, no vacuum or magnetic field or anything,"

They probably asked "plasma astrophysicists" or theoretical physicists (who have never seen a plasma in a lab) , otherwise known as plasma ignoramuses. This is precisely why jonesdumb and other who claim this or that plasma phenomena is not possible can be disregarded completely, their ignorance of plasma processes knows no bounds. The plasma cares not what the maths says is possible, the plasma just does its thing.

Nov 16, 2017
... The plasma cares not what the maths says is possible, the plasma just does its thing.

This is true for just about any natural phenomena. Human arrogance knows no bounds.

"There are more things in heaven and earth, Horatio,
than are dreamt of in your philosophy."

-- William Shakespeare

Nov 16, 2017
@idiot illiterate pseudoscience eu cult member
They probably asked "plasma astrophysicists" or theoretical physicists (who have never seen a plasma in a lab)
i find it hilarious that you would include a lab that repeatedly refutes your own claim that astrophysicists don't learn plasma physics

moreover, i should tell you that you're barking wrong about the above claims:
Professor Gharib's current research interests in conventional fluid dynamics and aeronautics
whoopsie! your prof you admire for being not an ignoramus studies MHD because it works!
LMFAO

epic fail

PS - the rest of your diatribe is a blatantly false claim wrapped in delusional fanatical rhetoric based upon your completely debunked eu religion

Nov 18, 2017
Take a look at the video, a number of ubiquitous plasma phenomena are shown;
First there are the concentric rings, similar to the coma of a comet, or this;
https://en.m.wiki...bula.jpg
Then there is another ring that is similar to this;
https://www.jpl.n...2006-005
And last but not least the "beams of light" that look remarkably similar to the jets on comets;
https://youtu.be/kDQSciYTq_s
And what is the common theme, plasmas and the electrodynamic processes which are primarily responsible for driving these interactions.

Nov 18, 2017
Similar to, similar to, similar to...Phenomenally inept display of "it looks like a duck therefore it most probably is a duck". Do you attempt to pay for your groceries with Monopoly money? Do you eat apples made of wax? Do you go walkies with a stuffed dog?

This is not how science works, buster!

Nov 18, 2017
Plasma is plasma, laboratory experiments which show plasma phenomena are completely relevant.
'Plasma from lasers can shed light on cosmic rays, solar eruptions'
https://phys.org/...lar.html
https://phys.org/...ets.html
https://phys.org/...ory.html
https://phys.org/...ous.html

"We have to learn again that science without contact with experiments is an enterprise which is likely to go completely astray into imaginary conjecture." Hannes Alfvén
Laboratory experiments regardless of the discipline are largely analogues of reality, it's how science works.

Nov 18, 2017
Take a look at the video, a number of ubiquitous plasma phenomena are shown;
First there are the concentric rings, similar to the coma of a comet, or this;
https://en.m.wiki...bula.jpg
And what is the common theme, plasmas and the electrodynamic processes which are primarily responsible for driving these interactions.


And, as Alfven himself said, in situ observations are the best of all. And we've just had a s/c at a comet for 2+ years. So, it's a good thing we didn't go with your 'looks like a duck' science, eh, because it's wrong.

Nov 18, 2017
"We have to learn again that science without contact with experiments is an enterprise which is likely to go completely astray into imaginary conjecture." Hannes Alfvén
Laboratory experiments regardless of the discipline are largely analogues of reality, it's how science works.


http://mrx.pppl.gov/

Nov 18, 2017
Experiments are one thing, but what you're doing is not experimentation, but looking at pictures taken during experiments (performed by scientists, no less!), and making implausible and unfounded conjectures based only on how things look in the pictures.

You want so desperately to find some correlation between what you believe and what you see in those pictures, that you suspend disbelief, abandon reason and critical judgment, and proclaim that the EU Lord has landed in a big pink sledge pulled by unicorns.

There are fools, damned fools, and then there's the EU.

Nov 18, 2017
@idiot illiterate pseudoscience eu cult member cd
Plasma is plasma, laboratory experiments which show plasma phenomena are completely relevant
yes and no
for starters, you are making ASSumptions about plasma without knowing actual plasma physics, then you claim you're correct because you believe it

what you should do is either:
1- learn plasma physics - https://ocw.mit.e...=physics

*or*

2- allow actual electrical engineers with astrophysics knowledge show you real physics, like here: https://phys.org/...asa.html

and before you mention the idiot EE promoting the eu cult, remember one thing: he has absolutely no knowledge of astrophysics, whereas someone like Hasegawa studied Electrical Engineering *and* astrophysics and is mimicing real phenomenon while proving, with evidence, that you're an idiot fanatical cult member

Nov 18, 2017
There are fools, damned fools, and then there's the EU.


"EU".....the European Union?

Nov 19, 2017
I hope they will study how the RF is dependent of the setup parameters like water velocity. They could also test what effect voltage between the water sorce and target plate has. Maybe it will modulate the ring or RF.

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