Tokamak Energy news

Point out news stories, on the net or in mainstream media, related to polywell fusion.

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Skipjack
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Re: Tokamak Energy news

Postby Skipjack » Thu Oct 06, 2016 8:35 pm

Here is some more about TE current plans and research as presented at the ICEF in Tokyo, this week:
http://www.icef-forum.org/platform/spea ... 161003.pdf

crowberry
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Re: Tokamak Energy news

Postby crowberry » Fri Oct 07, 2016 7:22 am

Thanks Skipjack, this is an interesting presentation. I have not previously seen this idea with merging/reconnection heating in the connection with spherical tokamaks.

paperburn1
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Re: Tokamak Energy news

Postby paperburn1 » Fri Oct 21, 2016 2:40 pm

http://www.utilitydive.com/news/mit-bre ... es/428797/
MIT has been working with the Alcator C-Mod for more than 20 years, repeatedly topping the record for plasma pressure in a magnetic confinement device. According to the Institute, the previous record of 1.77 atmospheres was set in 2005. While setting the new record of 2.05 atmospheres, MIT said the temperature inside Alcator C-Mod reached over 35 million degrees Celsius
I am not a nuclear physicist, but play one on the internet.

D Tibbets
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Re: Tokamak Energy news

Postby D Tibbets » Mon Oct 24, 2016 2:31 pm

paperburn1 wrote:http://www.utilitydive.com/news/mit-breaks-nuclear-fusion-record-in-bid-to-unlock-new-clean-energy-sources/428797/
MIT has been working with the Alcator C-Mod for more than 20 years, repeatedly topping the record for plasma pressure in a magnetic confinement device. According to the Institute, the previous record of 1.77 atmospheres was set in 2005. While setting the new record of 2.05 atmospheres, MIT said the temperature inside Alcator C-Mod reached over 35 million degrees Celsius


35 million degrees is close, but still no cigar- The bare minimum is at least 55 million degrees- 5 KeV for a thermalized plasma. Temperatures 3-8 times that are more attractive goals for burning D-T fuel. Still ~3 Kev is ahead of any publicized performance for FRC (I think), etc. I'm pretty sure JET has surpassed 5 KeV. I don't know about Japanese or Chinese efforts.

The real issue with this pressure though is confinement times. 10^25 particles per cubic meter is impressive, but only if confinement keeps pace. The old triple product issue (temperature * density * Confinement time). If they have achieved these densities with good or promising improved magnetic confinement- ie: limiting cross field transport either through huge size and/ or very strong magnets, and also, perhaps even more importantly- substantially reduced the edge instabilities/ MHD instabilities/ macro instabilities; then, yes, this would be impressive.

While fusion rate may scale as the square of the density, ExB losses, and Edge instabilities also scale as ~ the square of the density. You are essentially spinning your wheels, unless you can modify the loss picture.

Dan Tibbets
Last edited by D Tibbets on Mon Oct 24, 2016 2:33 pm, edited 1 time in total.
To error is human... and I'm very human.

Skipjack
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Re: Tokamak Energy news

Postby Skipjack » Mon Oct 24, 2016 9:53 pm

D Tibbets wrote:While fusion rate may scale as the square of the density, ExB losses, and Edge instabilities also scale as ~ the square of the density. You are essentially spinning your wheels, unless you can modify the loss picture.
Dan Tibbets

From Dennis Whyte's presentation, I thought it was actually getting more stable with increased magnetic fields.

paperburn1
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Re: Tokamak Energy news

Postby paperburn1 » Mon Oct 24, 2016 10:00 pm

First of all, congratulations to your results and to the media coverage you got!

•(1) What were the plasma temperature and density during that record shot ?


•(2) What was the background magnetic field strength and the related plasma beta value ?


•(3) What made that shot a record shot, i.e. was it particularly high heating power or better <something> than usual ?


•(4) For how long could you sustain that record pressure ?


•(5) Did you do it on purpose at the very end of the experiment's life because you were afraid of unusual high power fluxes (due to the high pressure) to the plasma-facing components ?


•(6) Did the plasma-facing components (or anything else) got any damage during that record discharge ?


•(7) What will happen now with the Alcator C-mod device and the people working on it ?


•(8) If I understand it correctly, your approach is somewhat different (although very similar) to ITER in that sense that you have a rather small device achieving nevertheless high density and temperature due to the higher magnetic field (correct me if I am wrong). There was once a device called “IGNITOR” which was planned to achieve some fusion power output, do you know the status of that device ?


•(9) Does the comparable high magnetic field strength in your approach prevent you from using superconductors at a reactor size level (or IGNITOR-size) ?


•(10) Will the scientific details about that shot be presented somewhere (or are they already somewhere?) ?


•(11) Does this record shot have a scientific significance or was it more something like “let's see what we can squeeze out of that device” ?


•(12) Thank you very much for reading all those questions and maybe even trying to answer them :)


I wish you all the best for your future.
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[–]MIT_PSFCPlasma Science and Fusion Center[S] 21 points 4 days ago




Great, technical questions. I'll try my best to put this into laymen terms.

Check out the FAQ about the record shot for more info: https://www.psfc.mit.edu/news/2016/pressure-record-faq

(1) The plasma temperature and density during the record shot was about 30Million C in the center, the density was 5*1020 ions per cubic meter. To put this into perspective, the 2 atmosphere shot was like gas at 100,000 times hotter and 100,000 times less dense. The density was very high for a tokamak, while the temperature was not as high as been acheived on other tokamaks.

(2) The background magnet field was 5.7T or about 140,000x the Earth's magnetic field. The Beta was about 1% which is low for C-Mod.

Check out some other traces here: https://www.psfc.mit.edu/news/2016/pres ... -faq#q_3_5

(3) The record shot was not particularly unusual, just more highly tuned. We developed a better way to fuel the plasma to higher density for the record. But actually, we got very near record performance on shots that were very different in three different ways.

(4) The highest pressure shot had nearly that high of performance for the full anticipated length of 0.5s of heating power, it was not transient. Things had to be stopped because C-Mod's magnets were heating up from being on and the internal components were heating up from the power to and from the plasma. This is normal.

(5) There were many reasons to push this to the end of the experiments life time. One was we were learning as we go. We did not particularly stress the machine, only perhaps marginally more than usual. The scheduling for collaborators coming in also played an important part since many team members were traveling to C-Mod for the last day and we wanted everybody to participate. More can be found here https://www.psfc.mit.edu/news/2016/pres ... -faq#q_3_7

(6) We do no think we damaged anything. We did not see any deleterious effects in the plasma nor on cameras or signals and plasmas ran well afterwards. We'll go inside the machine to inspect next week. See how we do this: https://www.youtube.com/watch?v=q3pQgozt3cM

(7) The device is now undergoing various calibrations so we can interprete the reams of data. Once we're done with that we'll put it in "cold storage" which is one step up from mothballing it. It is unclear what it's future is. We'd like to see it used for something scientifically interesting (Like converting it for this experiment: http://www.psfc.mit.edu/research/topics ... experiment) but it will be up to the DOE. The science team will continue to analyze data from C-Mod and will also continue collaborating as a team on the other facilities around the world. We are at the same time developing new technologies that will enable another generation of even more powerful tokamak reactor.

(8) Our device is similar to all tokamaks which includes ITER and IGNITOR. These devices are distingished by two important parameters, their size and magnetic field. If you make the field higher the size can be smaller and it is very non-linear. But there are limits from technology for the magnets. IGNITOR is still a Russian-Italy project but has not seen much progress recently due to funding, likely due to econimic down-turns.

(9) Previously the high field approach with tokamaks required using copper magnets (like C-Mod and IGNITOR) because superconductors don't work at the required magnetic field. However, we're really excited about building tokamaks at around or above 10T using new high-temperature superconductors: http://news.mit.edu/2015/small-modular- ... plant-0810. This new magnet technology enables IGNITOR sized experiments that could simply not be done with superconductors before. But for a toroidal reactor (like a tokamak or stellerator) the minimium size is set by the neutrons penetrating the wall and getting to the magnet.

(10) The scientific details were presented at the IAEA fusion conference this week at Kyoto http://www-pub.iaea.org/iaeameetings/48 ... Conference This is the premier world-wide conference. The results will be published in a journal article that will come out soon (it is a slow process) The results will also be presented in two weeks at the American Physics Society's Plasma Physics meeting in San Jose which is the annual large conference on plasma physics.

(11) The record shot does have scientific significance because it was significantly higher and longer than had been done before and we used a new way to fuel that was somewhat unexpected to work. Additionally, the near-record shots were in some ways even more scientifically interesting since they saw new phenomenon in the edge of the plasma and expanded the range we could get favorable operation in many ways. All the of the shots expand the international database for how tokamaks work in new directions. ...Personally though, nothing beats passing through an integer in an important parameter. P=1.95atm just doesn't seem as good as p=2.05atm....

(12) You're welcome. Glad you asked some good questions.
•BM
I am not a nuclear physicist, but play one on the internet.

D Tibbets
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Re: Tokamak Energy news

Postby D Tibbets » Tue Oct 25, 2016 9:07 pm

A density of 10^20 particles per cubic meter is more in line with with what I understand to be reasonable tokamak performance. Via pv=nrt, i can see the pressure being represented as several atmospheres. Is one half second confinement good? I've had the impression that several hundred seconds is necessary for breakeven with DT fuel at a density of ~ 10^ 19 to 10^20 particles per cubic meter, and temperatures perhaps ten times higher. I suppose the real significance is relative. How much better than previous results and what has been learned that allows further improvements.

I am currently under the impression that edge instabilities is the dominating issue challenging further advancement. I'm far from being knowledgeable in the area, but I have read that monitoring,intervening, understanding the processes and modes has made real strides in recent years.

Dan Tibbets
To error is human... and I'm very human.

paperburn1
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Re: Tokamak Energy news

Postby paperburn1 » Tue Oct 25, 2016 11:35 pm

No I do not think .5 seconds is good After further reading It looks like the shuffled the Ol'e (temperature * density * Confinement time) equations around to make a density record in a bid to get some more funds. 2 Atmos sounds like a real breakthrough until you start looking and how they actually manage to do this. Meh.
I need to read the articles before I get too excited and post.
I am not a nuclear physicist, but play one on the internet.

paperburn1
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Re: Tokamak Energy news

Postby paperburn1 » Wed Nov 30, 2016 5:12 pm

Bye Bye birdie

http://www.bbc.com/news/science-environment-37777729

JET shutdown in 2018 due to BRIEXT
I am not a nuclear physicist, but play one on the internet.

Giorgio
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Re: Tokamak Energy news

Postby Giorgio » Wed Nov 30, 2016 6:28 pm

I don't think that is going to happen and the article is not saying it.
They just list potential scenarios and add some pathos to keep the reader reading till the end.

Truth is that like many other shared researches and projects they will end up in the big cauldron of renegotiation that will happen any time soon.
Point is that Europe can't lose UK market and UK can't lose Europe market. That said, an agreement to keep the flow of goods, people, services and shared projects will be found simply because no one can afford the opposite.
CCFE will keep working as usual like if nothing happened.
Look, stars!

crowberry
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Re: Tokamak Energy news

Postby crowberry » Thu Dec 01, 2016 9:15 am

Here is another article written after the previous article was published: Post-Brexit business as usual at JET

crowberry
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Re: Tokamak Energy news

Postby crowberry » Mon Dec 12, 2016 10:27 am

Tokamak Energy has published a nice and illuminating 3 min 59 s long video on the construction of their next device the ST-40.
https://www.youtube.com/watch?v=jRyUWOUk_48

Inside information on ST40 - the compact, high-field tokamak currently under construction at Tokamak Energy. This video shows the main elements of ST40 and how they come together to form the whole tokamak.

Presented by Dr Melanie Windridge; featuring Greg Brittles and Otto Asunta. Animations by Prion Cutting Edge.

D Tibbets
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Re: Tokamak Energy news

Postby D Tibbets » Wed Dec 14, 2016 5:57 am

crowberry wrote:Tokamak Energy has published a nice and illuminating 3 min 59 s long video on the construction of their next device the ST-40.
https://www.youtube.com/watch?v=jRyUWOUk_48

Inside information on ST40 - the compact, high-field tokamak currently under construction at Tokamak Energy. This video shows the main elements of ST40 and how they come together to form the whole tokamak.

Presented by Dr Melanie Windridge; featuring Greg Brittles and Otto Asunta. Animations by Prion Cutting Edge.


A further link from the above video UTube page

https://www.youtube.com/watch?v=CbMpEtP245A

provides an argument for supporting ST-40 over ITER, as the speaker claims that while increasing size solves some problems, it introduces additional complications that counterbalance against progress. Smaller and denser machines like higher Beta Tokamaks are a better candidate for further research. He is championing the ST-40, but also all of the other higher density approaches like FRC, Polywell, Lockheed design, etc.

If only funds were actually proportioned based on this consideration....


Dan Tibbets
To error is human... and I'm very human.

D Tibbets
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Re: Tokamak Energy news

Postby D Tibbets » Wed Dec 14, 2016 6:06 am

Speaking of smaller machines, the German Stellarator released some recent press. No, link as it doesn't really say much about the physics of the approach. What it provides is engineering testing, which they say indicates the shape of the complex magnetic fields match very closely the theoretical projections. This does mean that once they get around to doing plasma testing, they should get results that are highly predictive- computer modeling should be testable at high accuracy and precision. How this will hold up at different scales is possibly the biggest question. Hopefully it will prove more consistent than the rocky road traveled by Tokamaks.

Dan Tibbets
To error is human... and I'm very human.

crowberry
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Re: Tokamak Energy news

Postby crowberry » Thu Dec 22, 2016 3:20 pm

Tokamak Energy, one of the world’s leading private fusion energy ventures, has received a major investment boost totalling £10M from Legal & General Capital and British billionaire David Harding.


http://www.tokamakenergy.co.uk/press/


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