Tokamak experiments come clean about impurity transport

Nov 10, 2011
Results from a recent turbulence simulation reveal turbulent structures believed to be responsible for the measured levels of impurity transport. Credit: Nathan Howard, MIT

A fusion reactor operates best when the hot plasma inside it consists only of fusion fuel (hydrogen's heavy isotopes, deuterium and tritium), much as a car runs best with a clean engine. But fusion fuel reactions at the heart of magnetic fusion reactors also create leftovers—helium "ash." The buildup of this helium ash and other impurities can cool the hot plasma and reduce fusion power. Research at the MIT Plasma Science and Fusion Center is providing new insight into the transport of these impurities in fusion plasmas in an effort to improve on the natural impurity exhaust process, producing cleaner plasmas and higher fusion power.

On the Alcator C-Mod tokamak at MIT, researchers are using a novel set of plasma diagnostics and advanced computer simulations to better understand the physical processes that can either flush out or allow them to stay. All fusion plasmas contain intrinsic impurities introduced by the unintentional interaction of very hot plasma with the reactor walls and the fusion reactions themselves. To study these phenomena, the scientists introduce a known source of impurities at a small level that will not adversely affect the plasma's performance. This is achieved using a high powered, pulsed laser to knock impurity atoms off a coated glass slide directly into the plasma edge. Once inside the plasma, the impurity is ionized and heated by the plasma and begins to emit soft x-ray radiation which is observed by a new high-resolution spectrometer that allows the impurities to be tracked as they are transported by plasma turbulence.

"It is not enough to simply observe results in existing experiments," says MIT graduate student Nathan Howard. "We also need to develop high resolution computer models to predict how impurities will behave in future larger, hotter reactors. The process is much like developing accurate long-range weather forecasts."

The MIT scientists are developing and testing new computer programs which run on some of the world's fastest supercomputers. A single case can take up to 250,000 CPU hours to complete. For comparison, this is roughly equivalent to letting a home computer run for about 15 years. The latest simulations connect the behavior of small turbulent eddies and ripples in the plasma to new measurements showing the movement of impurities into and out of the .

According to Dr. Martin Greenwald, Nathan's thesis advisor, "This work represents an important first step in gaining confidence in our ability to predict and control impurity transport in tokamaks."

Explore further: Scientists use plasma shaping to control turbulence in stellarators

Provided by American Physical Society

4.2 /5 (5 votes)

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User comments : 23

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Vendicar_Decarian
0.5 / 5 (39) Nov 11, 2011
What a shame that E-Cat has turned to be such a spectacular SCAM.
rawa1
1.4 / 5 (10) Nov 11, 2011
What a shame, some people still support the expensive and yet unsuccessful experiments leading to centralized energy sources, while they're ignoring twenty years of successful research of Piantelli and Focardi and the E-Cat technology, which is apparently based on this research.
antialias_physorg
5 / 5 (8) Nov 11, 2011
which is apparently based on this research.


This is 'apparent' by...?

Careful theoretical work and publications?
Demonstrated and verified experiment?

Or simply someone's say-so?
rawa1
1 / 5 (8) Nov 11, 2011
Demonstrated and verified experiment?
Because Mr. Focardi is sitting right near the E-cat device as one of its inventors.

http://newenergya...2011.jpg

http://timesofind...i/videos

So, do you presume, the technology developed with prof. Focardi is working, but he intentionally didn't use it during E-cat public demonstrations for to appear like complete troll and fraudster later?

Sometimes I've troubles to understand the way, in which apparently most of normal intelligent people are "thinking" here.
antialias_physorg
5 / 5 (7) Nov 11, 2011
Just that I have seen no verified, controlled experiments. A lot of handwaving, charging people for having a look at it, unknown buyers, press releases before publications...

...all the hallmarks of a scam.

I'm not holding my breath how this one turns out.

I'll gladly be surprised - but until then I'll go with snake oil. Seems much more legit.
rawa1
1 / 5 (6) Nov 11, 2011
but until then I'll go with snake oil. Seems much more legit
The people, who are boycotting the cold fusion research should pay to those, which are supporting it. We are losing money twenty years just because most of people are fraudulent sceptics. These people don't risk anything with their scepticism - so they should pay for it.

The problem simply is, the same situation can appear again and again and all important findings would be ignored. The society has no feedback mechanism for the case of sceptic failure implemented. This asymmetry slows down the progress of human civilization a lot.
antialias_physorg
5 / 5 (8) Nov 11, 2011
Soooo..I should pay for a percived scam? Isn't that the point of a successfull scam? No, thanks - I'll pass.

You may pay, though, as much as you like. Be my guest. And I will gladly accept that all the benefit/profit that will come in the future off this miraculous technology will go to you as shareholder (including the dividends from profit money from my utilities bill once I get my energy off off industrial sized ECATs.)

No really. Take it. I insist. It will be my way of saying: you were right, I was wrong.
CHollman82
1.8 / 5 (8) Nov 11, 2011
but until then I'll go with snake oil. Seems much more legit
The people, who are boycotting the cold fusion research should pay to those, which are supporting it. We are losing money twenty years just because most of people are fraudulent sceptics. These people don't risk anything with their scepticism - so they should pay for it.

The problem simply is, the same situation can appear again and again and all important findings would be ignored. The society has no feedback mechanism for the case of sceptic failure implemented. This asymmetry slows down the progress of human civilization a lot.


Are you serious? If it works they will make billions, that is how legitimate ideas are protected from skeptics...

(FYI, skeptic is spelled with a 'k', and commas only belong where one would naturally pause when reading the sentence aloud...)
rawa1
1.2 / 5 (6) Nov 11, 2011
If it works they will make billions, that is how legitimate ideas are protected from skeptics...

Why not to suspend all basic research and to kill all fresh born children? They don't bring any money, billions the less...

This is just the problem, the strictly utilitarian criterion doesn't work at the case of basic research. But from some reason, the people are refusing to consider anything related to low energy nuclear reactions as a basic research. All previous findings and indicia are simply ignored, the people just care about applied research in form of final working device. The pathological skepticims is just in the application of double standards to the doubted subject.

BTW Thank you for the "skeptic" word correction. My spell checker in Firefox seems to hate this word obstinately.
DontBeBlind
3.3 / 5 (3) Nov 11, 2011
The whole E-Cat deal has something wrong with it. If its about making money if he would prove that it actually works then he would get many more interested people. And if this was for the us military as some say. Then don't we already know to much about it for that to be true. To recap hope it works doubt it will.
rawa1
1 / 5 (3) Nov 11, 2011
If this technology will remain in hands of US Army only, it will never become useful for human civilization as a whole. Fortunately, prof. Piantelli and others are working on more opened version of nickel fusion and I'd urge all research institutions to join to this research too. The ignorance of public research just supports the people, who would like to keep this technology closed for ever. After all, in the same way, like the support of alternative technologies (like the tokamak fusion) which can never remain opened by their very nature.
bluehigh
2.3 / 5 (6) Nov 11, 2011
skeptic is spelled with a 'k'
-Chollman

Only in North America - you insular ignoramus.

http://oxforddict.../sceptic

rawa1
2 / 5 (4) Nov 11, 2011
..OK, my apology goes back to my lovely Firefox spellchecker.
Eoprime
5 / 5 (2) Nov 11, 2011
skeptic is spelled with a 'k'

-Chollman
..OK, my apology goes back to my lovely Firefox spellchecker.

-rawa

You talk to yourself?
typicalguy
not rated yet Nov 12, 2011
Hey, I was abducted by aliens. I stole technology from the ship and am willing to show it to you if you pay me cash. You can't touch it and it will be in a sealed black box. Trust me, it is in there, working alien tech. You can see the box it resides in if you pay me money. I would love for this cold fusion to be true but until this is released for others to duplicate, it will be in the 'a sucker is born every minute' category. I'm amazed that people are willing to believe this stuff when he doesn't release details for duplication.
Callippo
not rated yet Nov 12, 2011
In recent time we are facing increasing frequency of articles about tokamaks at the PhysOrg site, which is similar to PR campaign following the start of LHC. These articles have no other purpose, than just convince the public into funding of hot fusion research under the situation, when cold fusion proved its usefulness.

At the moment, when cold fusion is proven real (and nothing prohibited the physicists to prove it during last twenty years with exception of their fear of lost of job) - then the tokamak technology (and all similar technologies based on hot fusion) will become essentially useless from many reasons. The main problem is, the hot fusion is not scalable and it generates many neutrons, which are doing whole experimental device radioactive after while. In addition, it requires to solve huge number of additional technical problems, which otherwise would never exist. In another words, such a devices are becoming a salary generators for people involved without real value.
krwhite
5 / 5 (2) Nov 12, 2011
If cold fusion was feasible, that would create countless billion dollar grants worldwide to study it. Thanks for playing the [its greed preventing this research] game.
Vendicar_Decarian
0.3 / 5 (36) Nov 12, 2011
"We are losing money twenty years just because most of people are fraudulent sceptics. These people don't risk anything with their scepticism - so they should pay for it." - Rawa

When can I expect payment from you for your failure to believe my skepticism?

Vendicar_Decarian
0.3 / 5 (36) Nov 12, 2011
"These articles have no other purpose, than just convince the public into funding of hot fusion research under the situation, when cold fusion proved its usefulness." - Callipo

Damn. Another Illuminati conspiracy exposed.

The MIBs are out for you now Callipo. You might get disappeared.

Vendicar_Decarian
0.5 / 5 (37) Nov 12, 2011
"Hey, I was abducted by aliens. I stole technology from the ship and am willing to show it to you if you pay me cash." - TypicalGuy

I can vouch for Typical Guy. He showed me and it changed my life.

He also showed RyggTard, but it didn't change his lowlife.

TypicalGuy has a potential buyer for the alien technology. Unfortunately his name is secret, as well as the name of his home planet.

Rumor has it though that the buyer is from Planet MetaLuna.

Vendicar_Decarian
0.3 / 5 (36) Nov 12, 2011
"The ignorance of public research just supports the people, who would like to keep this technology closed for ever." - Rawa

Well......... If that is the concern, then why keep the secret recipe that makes it all work secret?

Just drop off a working prototype to the New York Times and the secret is out.

Or are they part of the conspiracy of silence as well?
Vendicar_Decarian
0.2 / 5 (35) Nov 12, 2011
"Why not to suspend all basic research and to kill all fresh born children?" - Rawa

"Delicious" fresh born children.
Vendicar_Decarian
0.3 / 5 (36) Nov 12, 2011
"they're ignoring twenty years of successful research of Piantelli and Focardi" - Rawa

What a shame they can't demonstrate that success with anyone provably competent in the art watching and checking their work.

Why is that?