Major Milestone for Fusion Stellarator W 7-X

Reflections on fusion history, current events, and predictions for the 'fusion powered future.
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Dennis P Brown
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Major Milestone for Fusion Stellarator W 7-X

Post by Dennis P Brown »

The most promising and successful (to date) major fusion reactor - the Wendeltein 7-X - has successfully cooled its superconducting magnets down to 4 K and run the entire stellarator "torus" up to full current (nearly 13,000 amps)/field strength and created the predicted/required field. The device is set for a first light plasma before the end of this year. Getting the revolutionary and exceedingly complex magnetic super conductors that form the undulating torus to all work together and create the required field is the critical achievement for any stellarator concept - the later goal will be tested with first plasma before the year is out. The fact that this machine (incorrect: my saying "should produce") will be heated using* 10 Mega-watts for 30 minutes will be a game changer - and unlike ITER - this machine is finished and the complex field coil system is fully working as designed! This machine is a game changer if it achieves its stated goals. While, to date, so many other programs have promised much and delivered little (ITER, NIF), these people have a finished a machine that has demonstrated the most critical technological goal required for a successful stellarator to operate. Here is the site of the news release: https://www.ipp.mpg.de/3895159/06_15

Here is a good article on this program and why this device has only been possible today and how it differs from Tokamaks - its advantages and dis-advantages. See: https://www.iter.org/newsline/172/680

* thanks Jeroen Vriesman for noting this serious error on my post and posting the correction!
Last edited by Dennis P Brown on Mon Jul 13, 2015 10:27 am, edited 2 times in total.
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Richard Hull
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Re: Major Milestone for Fusion Stellarator W 7-X

Post by Richard Hull »

A gaint leap backwards. A new stellarator! Lyman Spitzer would be proud.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
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Dennis P Brown
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Re: Major Milestone for Fusion Stellarator W 7-X

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Richard, I do believe Lyman Spitzer would be very pleased and proud as you add - the basic idea behind a Stellarator to prevent a major plasma instability that dogged all fusion devices back then as well as not requiring a massive induced current through a plasma was a brilliant breakthrough - just occurred too early compared to what technology was available in that very backward/ancient dark days in the 50's ... a time when fusion research scientist apparently only had "stone knives and bear skins" available to build their stellarators with ... lol. That the technology then was incapable of both designing and building the extremely complex magnets until very recently prevented these very unique devices from being useful. While a "leap backwards" in the literal sense of the word, this is a good thing - unlike a tokamak, stellarators can be run continuously and avoid a major plasma instability that no other design can directly address. Further, a stellarator does not need an "induced" central current to stabilize the plasma - an approach that makes continuous power generation very difficult and will not be validated even in ITER. As such, this device designed using super computers and exploiting revolutionary superconducting magnets is a major advance in fusion - this advanced stellarator (W-7X) will have a plasma that is innately stable; unlike a tokamak and most other magnetic based reactors - all of which use innately unstable configurations for their plasma's and struggle to maintain the plasma for just a few seconds - not minutes. By the way, the unique design that W-7X uses was tested in America a few years back and proven to be innately stable: just as theory described. That machine, however, was a small test bed with limit power so it only demonstrated the revolutionary torus/magnetic field design/concept as valid - didn't address scaling issues nor burning plasma's.

Further, as we all know, plasma fusion is extremely difficult and issues often appear "out-of-nowhere" that defeat the best laid plans ... this machine may be no different and teething pains will most likely occur (cutting edge almost requires these issues) - whether they kill or just delay this project will be seen as first "light" plasma is started this year and even more so as the machine is slowly upgraded to real plasma and will use hydrogen only (error in saying deuterium/tritium.) Still, if they do achieve stable plasma conditions (will be similar to ITER) for any significant time on a scale of many minutes to even just tens of minutes this will be a major breakthrough and a true game-changer. While I realize we have heard this siren song many times, this machine is based on very solid foundations of both theory and experiment using an "old" concept that did have many successful innovations that, in turn, were shown to be valid even then. Does it deserve a great deal of cautious doubt? Of course. Does it deserve immediate dismissal? - sorry, but this device has a lot of solid proof of both the theory and actual plasma testing in smaller machines; work that was done just a few years ago.

As for engineering - this machine has now passed many critical milestones with flying colors and is ready for plasma testing - tragically for all fusion programs to date, plasma physicist always spent decades playing with approaches and experiments chasing tiny instabilities in fruitless endeavors to control them while massive instabilities were ignored or simple, extremely well understood vacuum practices were utterly ignored that destroyed all early fusion work: I hope the people at this place aren't blinded by trivial experimental pursuits but rather, are focused and determined to press ahead with fusion. Time will tell whether fusion researchers or standard plasma physicist run this program but the breakthrough concept of this stellarator design is in fact revolutionary and deserves to be watched closely.
Last edited by Dennis P Brown on Mon Jul 13, 2015 11:56 am, edited 1 time in total.
Jeroen Vriesman
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Re: Major Milestone for Fusion Stellarator W 7-X

Post by Jeroen Vriesman »

Thanks for the link, really great, seems much more promising than tokamaks.

But the 10MW is not energy production, it's ECRH "electron cyclotron resonance heating".
In other words: it's not producing 10MW, the plasma is consuming 10MW.
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Richard Hull
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Re: Major Milestone for Fusion Stellarator W 7-X

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In the end, it is not what the physicists think or do or what the engineers do, but what the electrical utilities advised by their bean counters think, reacting to what they think they can get away with charging the public of electrical power that will determine fusions future, even with a total win in fusion energy production.

Richard Hull
Progress may have been a good thing once, but it just went on too long. - Yogi Berra
Fusion is the energy of the future....and it always will be
The more complex the idea put forward by the poor amateur, the more likely it will never see embodiment
billhunter
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Re: Major Milestone for Fusion Stellarator W 7-X

Post by billhunter »

It seems like the international fusion research community could hardly wait for it to happen.
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