Fiery sighting: A new physics of eruptions that damage fusion experiments

Fiery sighting: A new physics of eruptions that damage fusion experiments
Physicists Ahmed Diallo, front, and Julien Dominski. Credit: Elle Starkman/PPPL Office of Communications.

Sudden bursts of heat that can damage the inner walls of tokamak fusion experiments are a hurdle that operators of the facilities must overcome. Such bursts, called "edge localized modes (ELMs)," occur in doughnut-shaped tokamak devices that house the hot, charged plasma that is used to replicate on Earth the power that drives the sun and other stars. Now researchers at the U.S. Department of Energy's (DOE) Princeton Plasma Physics Laboratory (PPPL) have directly observed a possible and previously unknown process that can trigger damaging ELMs.

Working together, physicists Ahmed Diallo, an experimentalist, and Julien Dominski, a theorist, pieced together data from the DIII-D National Fusion Facility that General Atomics operates for the DOE in San Diego, to uncover a trigger for a particular type of ELM that does not fit into present models of ELM plasma destabilization. Their findings could shed light on the variety of mechanisms leading to the onset of ELMs and could broaden the portfolio of ELM suppression tools. Understanding ELM physics is crucial to developing fusion facilities that can fuse light elements in the form of plasma—the state of matter composed of and atomic nuclei—to produce a virtually inexhaustible supply of energy to generate electricity.

Puzzling data

The new observations, reported in Physical Review Letters, began as an effort to unravel puzzling data detected by probes of magnetic field and plasma density fluctuations during DIII-D experiments. The data showed the eruption of ELMs following periods of unusual quiescence. "These were special cases that didn't follow a standard model," said Diallo. "We started digging into this together," Dominski said. "It was a most interesting collaboration."

In roughly six months of joint research, the physicists uncovered previously unseen correlations of fluctuations in the DIII-D experiments. These correlations revealed the formation of two modes—or waves—at the edge of the that coupled together to generate a third mode. The newcomer then moved toward the wall of the tokamak—created a radial distortion in technical terms—that triggered bursts of low-frequency ELMs.

The ELMs were a type also seen on the Joint European Torus (JET) in the United Kingdom, the ASDEX Upgrade in Germany and other fusion devices following periods of quiescence. In principle, the results could also apply to systems such as solar flares and geomagnetic storms that are suddenly unleashed, according to the paper.

Opening a door

While the findings open a door on a method for triggering ELMs, they do not fully explain the process. The two physicists thus seek to analyze more data sets. "If we can fully understand how the triggering works we can block and reverse it," Diallo said.


Explore further

Steady as she goes: Scientists tame damaging plasma instabilities in fusion facilities

More information: A. Diallo et al, Direct Observation of Nonlinear Coupling between Pedestal Modes Leading to the Onset of Edge Localized Modes, Physical Review Letters (2018). DOI: 10.1103/PhysRevLett.121.235001
Journal information: Physical Review Letters

Citation: Fiery sighting: A new physics of eruptions that damage fusion experiments (2019, January 16) retrieved 24 April 2019 from https://phys.org/news/2019-01-fiery-sighting-physics-eruptions-fusion.html
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Jan 16, 2019
Former prisoners of alien visitors to our world had asked to see the power source of the alien ships and were shown, and had explained to them and likely witnessed the operating power source of the working fluid in an elaborate 'dance' on the way to generating energy. IMHO they witnessed a fusion cell in operation and were somehow able to see 'inside it' to witness this 'dance'. This article give a hint to our path to the alien device. Since this too has to obey laws of physics, then if there is 'new'(to us) physics then we need to earn it through research.

For over 500,000years, man did nought but chuck spears, literally. Then for 2000 years he had 'some' metal but did not see usefulness in Hero's steam 'engine'...called it a toy. Now in last 100 years we have gone from horses to rockets and jet fighters. War progress? Yes! Major progress almost always comes in wars! Now we battle time and bad politicos like Trump and Lysenko to save our planet before we all choke.

Jan 16, 2019
Former prisoners of alien visitors to our world...


Cool story, bro.

Jan 17, 2019
ELMs - reminds me of an old "Outer Limits" sci-fi story I once watched.

Jan 17, 2019
You wondering why the aliens would even bother to show off their technology to monkeys?
Yeah me neither.
I'm guessing the "wise" aliens thought the monkeys tasted delicious?

Yet won't show it to anybody modern & sane. with the intelligence. education & scientific training to appreciate such marvels?

This scenario is why.

"Ahh, Fleet Lord. Here is the monkey,you requested be brought to the bridge."

"Thank you Chef. I do enjoy playing with my food before you flambe them!"

"Here, I'll just remove the shock-collar. So you can enjoy chasing the monkey around the Bridge."

Just then a Signals Ensign interrupted "I beg your pardon Sir. But Tyranny Central has sent you a message recalling this Fleet."

Glumly he officer muttered "Oh pooh!"

Suddenly the Ensign yelped in surprise, pointing at the monkey. Now on the at the command Desk idly poking at the sparkling lights.
When, at random. it triggered the Fleet self-destruct code.

At least my story is rational.

Jan 17, 2019
This has been known before 1998

It is still not solved as of 1019, that's 21years of not solving a problem
which while unsolved
fusion remains a dream, as on top of other more mundane problems
this ELM problem has halted fusion for 21years with no solution in sight
mainly
because we are only just begging to observe this problem
in fact this problem has diverted attention away from fusion
and become an academic interest in its own right
it is a process in the sun
which suggest these fusion reactors are subterfuge for research on other subjects

Jan 18, 2019
granny, you are just so damn selfish! All these years since 1019, you had all the secrets to successful fusion power generation & yet refused to patent your discovery & build one.

{shaking my head in disbelief}

Jan 18, 2019
This eternity of fusion
rrwillsj, fusion power 1019
Just watching transporting wood pellets from America to DRAX power station
the logistics to keep power stations supplied with fuel use as much fuel as the DRAX its self
that date, rrwillsj a Freudian slip
as there is another way to production of electricity
in each home
without this reliance on massive power stations and burdensome infrastructures
so since it seems as if we've been waiting since 1019 we could in 10019
still seem as though we are waiting
as these fusion laboratories are writing research thesis on "edge localized modes" receiving the obligatory Nobel prizes for their and advancement into solar process in "solar edge localized modes
in energetic in high temperature plasmatic magnetism"
In the meantime in 10019 as we put the last log of fuel in DRAX as the last light goes out
and with it the Giga watt power stations powering our fusion laboratories
Previously known as fusion reactors

Jan 18, 2019
My definition of woohoodwink versus Real Science remains:

Show us the working prototype. Allow expert engineers to test it & take it apart & put it back together & get it running again. To the satisfaction of the US Patent process.

Otherwise, you are just a fraud.

Claiming to be an expert of technology you lack the competency to build?

Why should anyone value your unproven opinion?
As you have nothing to show for your chronic waste of commentaries but your empty words.

Jan 19, 2019
Oh! The irony

Rrwillsj, as solar power is fusion power
these Giga watt power stations powering our fusion reactors
without these Giga watt power stations
these experimental
fusion reactors, will come to a grinding halt
so
rrwillsj, as you bask in the heat from your solar power electricity
as you bathe in the limitless hot water from solar power electricity
spare a thought
for
these poor fusion reactors
as
they use fossil fuelled Giga watt power stations
To keep their million degree fusion fires burning!

Jan 19, 2019
Rrwillsj, if you are referring
to
"as there is another way to production of electricity
in each home"
this
was put to one and all
as you recall
as
you recall the outcome
as "Isaac", recalls most vividly

Jan 19, 2019
The Ethos of why Fusion fails

Take a typical example
"Sudden bursts of heat that can damage the inner walls of tokamak fusion experiments are a hurdle that operators of the facilities must overcome"
Why fusion fails
fusion needs heat
millions of degrees of heat
and
what do we do
when this heat materialises
we approach is as "a hurdle that operators of the facilities must overcome"
effectively
to
reduce heat damage to the reactor walls
to prevent sintering
we
reduce the temperature of the "Sudden bursts of heat"
as these "Sudden bursts of heat, occur in the Sun
occur in the solar process
they are a requisite process of fusion
so
as we stabilise
as we control
we
cool this vital burst of energy
this fusion reactor is releasing
as it is copying the real solar process, our Sun
we have to increase this ELM
we have to move the reactor walls further back
we have to increase this size of this fusion reactor
We need higher temperatures, not less

Jan 19, 2019
So.... granny, uhmm...
So now you are claiming credit for the Sun burning brightly?

Would you define that as omniscience or omnipotence?
Cause my definitions will be a lot less polite to a deity's delicate ears.

When you arrive at the US Patent Office, to solicit their permission to apply?

Puh! Leeaaze!
Let me know in advance that I can make the trip to DC.

To observe as you hand over your patent application, with working prototype(as per their rules).


That I may be standing there.
To witness the expression on the clerk's face as you explain to her what you are presenting.

I will die of laughter.
But what a way to go!

Jan 21, 2019
Do not forget your urn
rrwillsj> That I may be standing there.
To witness the expression on the clerk's face as you explain to her what you are presenting.

I will die of laughter.
But what a way to go!

And
so, rrwillsj
to prove the proof of concept
to this shell shocked patent clerk
a demonstration of cremating your ashes
So do not forget your urn, rrwillsj

Jan 22, 2019
dribble

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