This is it!! again....

Reflections on fusion history, current events, and predictions for the 'fusion powered future.
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Richard Hull
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This is it!! again....

Post by Richard Hull » Wed Aug 01, 2018 4:32 pm

I hate doing this, but here it is in all its hyper- press released glory, far from scientific scrutiny or study.

https://www.forbes.com/sites/arielcohen ... 81655a4c49

Looks like a remake of the mirror machine of the 50's just like the Stellarator. All that is old is new again.

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
Retired now...Doing only what I want and not what I should...every day is a saturday.

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Dennis P Brown
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Re: This is it!! again....

Post by Dennis P Brown » Thu Aug 02, 2018 10:11 am

Again, I must interject a few words about "old design" stellarator and some more relevant words on that mirror machine: Stellarators have advanced in ways that no one could have imagined twenty years ago. Currently, stellarators have taken a few orders of magnitude improvement in plasma confinement compared to earlier models. This is solely due to the incredible capabilities of super computers (making amazing advances in magnet design) and the truly fantastic ability to use computer controlled manufacturing to create very complex super conducting magnets (scary how convoluted those magnets shapes are but essential to their goal; why no one could take these machines serious in the 70's until this advancement was achieved.)

Now, the old idea of a straight magnetic bottle with leaking ends partly 'sealed' using so-called "mirror" end magnets, or the classical mirror machine as done by Lochheed Martin (L-M) still has that issue of plasma lost out of the ends (causing rapid energy lost.) L-M just simply applies the same old, concept but uses a moderately stronger, though a more uniform field (strange that was their principle change - linear confnment was never the main problem for those machines.)

L-M has, as of last published report, created a very unimpressive plasma density for all of one milli-sec. Yes, L-M achieved a better Beta confinement compared to the original machines. But as posted here not too long ago, even the polywell can boast a far better Beta value though that was only for electron confinement; a rather different issue compared to a typical fusion machine that has both protons and electrons to confine; still, the one milli-sec, while impressive for a mirror machine, would be a bad joke for any current tokamac.

Despite what the article claims, this data was published but I see why the writer claims otherwise - LOL. The W-7 stellarator took a far denser plasma and held it for a few seconds (that is over three orders of magnitude better than L-M's device) and that was the W-7's very first run with its new wall coatings and diverter. The W-7 team is well on track to achieve their goals from their current results (their field is better than their models predicted meaning their magnet design/installation is better than they had hoped.). Of course, they still have a far way to go in order to achieve their 30 minute containment objective. Still a few seconds was and is a new record for that density using a stellarator and is a major improvement for this type of approach.

I cannot say enough about diverter technology impact on the field of plasma fusion devices - developed in the 80's, that single device is what took tokamacs that were terrible and allowed these machines to improve by a few orders of magnitude almost over-night in plasma density/confinement. Amazing what happens when physicist take a old and well understood idea in vacuum work and finally use it rather then just model even more complex solutions to a very bad design.

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