Helically Symmetric eXperiment (HSX) at UW More Efficient than Previous Stellarators

A research team, headed by electrical and computer engineering Professor David Anderson and research assistant John Canik at the University of Wisconsin-Madison, recently proved that the Helically Symmetric eXperiment (HSX) can overcome a major barrier in plasma research: Previous stellarators lost too much energy to reach the high temperatures needed for fusion.

Results show that the the odd-looking magnetic plasma chamber design of the HSX in fact loses less energy than previous stellarators, meaning that fusion in this type of stellarator could be possible.

Current plasma research builds on two types of magnetic plasma confinement devices, tokamaks and stellarators. The HSX aims to merge the best properties of both by giving a more stable stellarator the confinement of a more energetically efficient tokamak. "The slower energy comes out, the less power you have to put in, and the more economical the reactor is," says Canik.

Tokamaks, the current leader in the fusion race, are powered by plasma currents, which provide part of the magnetic field that confines the plasma. However, they are prone to “disruptions.”

“The problem is you need very large plasma currents and it’s not clear whether we’ll be able to drive that large of a current in a reactor-sized machine, or control it. It may blow itself apart,” says Canik.

Stellarators do not have currents, and therefore no disruptions, but they tend to lose energy at a high rate, known as transport. The external magnetic coils used to generate the plasma-confining field are partially responsible for the high transport rates in conventional stellarators. The coils add some ripple to the magnetic field, and the plasma can get trapped in the ripple and lost. 

The HSX is the first stellarator to use a quasi-symmetric magnetic field. The reactor itself looks futuristic: Twisted magnetic coils wrap around the warped doughnut-shaped chamber, with instruments and sensors protruding at odd angles. But the semi-helical coils that give the HSX its unique shape also direct the strength of the magnetic field, confining the plasma in a way that helps it retain energy.

The team designed and built the HSX with the prediction that quasisymmetry would reduce transport. As the team’s latest research shows, that’s exactly what it does. “This is the first demonstration that quasisymmetry works, and you can actually measure the reduction in transport that you get,” says Canik.

The next step for the project is to establish how much symmetry in the coils is necessary to achieve low transport rates. They hope to make the coils easier to engineer, with the mindset that the principles used in the HSX could someday be incorporated into fusion generators, the reason that Anderson and his team began designing the HSX 17 years ago.

“It’s an exciting field. It’s something where one can contribute positively to mankind with an energy source that’s completely sustainable, doesn’t involve nuclear proliferation or radioactive waste, with a limitless fuel supply,” says Anderson. “Plus, the machines look cool.”

In other fusion news from my alma mater, the U.S. Department of Energy has named a University of Wisconsin-Madison engineering professor Raymond J. Fonck to lead its Office of Fusion Energy Science (OFES), located within the DOE Office of Science. Fonck will direct a large portion of his efforts toward ITER, a seven-member international project designed to demonstrate the scientific and technological feasibility of fusion power. Fonck will take a research leave of absence from UW-Madison, where he directs the Pegasus Plasma Experiment, the third-largest fusion-research experiment of its kind in the world.

Comments

[donb]

Wow, they have been playing around with stellarators at UW Madison since I was an undergraduate there (BSEE 1973)!

Fusion power has been 25 years in the future for as long as I can remember.

[Fabio]

Why, why oh why do they keep playing with "hot fusion" when there's the cold one which has been proven to work since many years now?

Check this out: http://www.rainews24.rai.it/ran24/inchieste/19102006_rapporto41-eng.asp

[amazingdrx]

Cool Jim, mine too.

Star Trek becoming reality at the UW? Excellent.

[Jim]

I remember looking from the pharmacy lecture rooms down into the donut room(tokamak). It would be pretty cool if the UW could solve the great energy problem we now have!

BS Pharmacy 1990

Jim

[JeffS]

I too matriculated at the U of W. Go Bucky!

[Paul Dietz]

Why, why oh why do they keep playing with "hot fusion" when there's the cold one which has been proven to work since many years now?

Because that kind of cold fusion is mythical, sloppy science, self delusion, and outright fraud notwithstanding.

[Fabio]

"Because that kind of cold fusion is mythical, sloppy science, self delusion, and outright fraud notwithstanding."

That's bollocks, if you pass me the term, which is however in line with your own wording.

Have you read the link I gave? Please do. Have you watched the interview with the scientists of the ENEA, the italian national body for the alternative energies? Please do.

It's been proven to work, it does. Open your eyes. Rather, start reading.

For your conveninence, I'll directly link the video here: http://www.rainews24.rai.it/ran24/inchieste/video/18102006_rapporto41_eng.wmv

And the scientific paper here: http://www.rainews24.rai.it/ran24/inchieste/documenti/Fusione_Fredda.pdf

You'll also want to check this out: http://www.d2fusion.com, just in case.

[Paul Dietz]

That's bollocks,

Well, you're entitled to that opinion. Just be aware it's a gullible, stupid, and incorrect one.

As for that paper, I'll just note that cold fusion pseudoscientists may very well be able to reproduce, if not correctly understand, experimental artifacts. Production of 4He from DD fusion would produce copious amounts of readily detectable (indeed, dangerous) radiation, either gamma radiation or neutrons from (alpha,n) side reactions. And, if pseudoscientists try hard enough and long enough, they can eventually make experimental errors that look (to them) like real results.

[Fabio]

Paul Dietz, your "pseudoscientists" are part of the italian national body for alternative energies. What are your credentials?

Have you studied the paper? If so, please point out its fallacies.

Have you watched the video? What do you have to say about the transmutation process taking place in some of the experiments?

Please, state facts, rather than unsubstantiated opinions.

[Calamity]

"Have you studied the paper? If so, please point out its fallacies."

How about the fact that they don't talk about the potential for future energy generation? EROI (input vs output)? Economics? Safety? How to harness the excess enthalpy? Is it even practical at all? Because that's what an alternative energy body would look at...