New finding may explain heat loss in fusion reactors

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

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ohiovr
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New finding may explain heat loss in fusion reactors

Postby ohiovr » Tue Feb 16, 2016 2:50 pm

New finding may explain heat loss in fusion reactors
Solving a longstanding mystery, MIT experiments reveal two forms of turbulence interacting.

Summary:
A new computer model finds that electrons are more important in plasma interactions than previously believed. A simulation of more than 10 million computer hours has demonstrated that electrons are as important as ions for instablity and turbulence problems. The results of this simulation have been simplified into a new computer algorithm that can complete on an ordinary household computer in a reasonable period of time.

Turbulence is a long-standing problem that leads to heat losses in the plasma.

A long-standing discrepancy between predictions and observed results in test reactors has been called “the great unsolved problem” in understanding the turbulence that leads to a loss of heat in fusion reactors. Solving this discrepancy is critical for predicting the performance of new fusion reactors such as the huge international collaborative project called ITER, under construction in France.


http://news.mit.edu/2016/heat-loss-fusion-reactors-0121

Tom Ligon
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Re: New finding may explain heat loss in fusion reactors

Postby Tom Ligon » Tue Feb 16, 2016 4:20 pm

It will be interesting to see if this model is compatible with the Polywell, as it handles electrons very differently than other reactors. Dr. Park has a considerably different view of how a Polywell works than Dr. Bussard did. I don't know if he clings to the idea that the Polywell even needs to hold the ions at a monenergetic condition (edge thermalization at low energy), or depends so much on electrons and ions doing opposite things with energy.

I've gotten the impression that Dr. Park expects the plasma within the rather flat-bottomed diamagnetic region to be fairly conventional thermal plasma, although still slightly electron rich. Dr. Bussard's models showed a flat-bottomed "potential bucket" with a spike in the middle. Electron turbulence might mush that out.

mvanwink5
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Re: New finding may explain heat loss in fusion reactors

Postby mvanwink5 » Tue Feb 16, 2016 6:02 pm

The results offer clear, independent evidence that the electron-scale turbulence really does play an important role, and they show that this is a general phenomenon, not one specific to a particular reactor design.
That’s because Howard’s simulations were based on MIT’s Alcator C-Mod tokamak reactor, whereas Ruiz Ruiz’s results were from a different type of reactor called the National Spherical Torus Experiment, which has a significantly different configuration.
In other words turbulence resulting in heat dissipation is a two part problem and might not show up in a short duration test, which is the hallmark of past Polywell test reactors?

So, the proposed $30 million dollar EMC2 machine needs to be a continuous running machine?
Now, researchers at General Atomics are taking these new results and using them to develop a simplified, streamlined simulation that could be run on an ordinary laptop computer, Howard says.
Or does this new fast running code allow for simulation without the build?
Near term, cheap, dark horse fusion hits the air waves, GF - TED, LM - Announcement. The race is on.

Tom Ligon
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Re: New finding may explain heat loss in fusion reactors

Postby Tom Ligon » Tue Feb 16, 2016 6:27 pm

Or maybe electron turbulence does not matter much in a pulsed machine.

"Ordinary laptop computer." Translation, 20 years ago this would have been called a supercomputer. A large part of getting one to run this way is to strip them back to the essentials and write tight code. Scrap Windows. Maybe install just the Linux kernel so you can boot it, and then let the software rip with no interruptions.

My desktop machine, The Mighty Teraquad, is built on an 8-core Intel i7-3770. It sports 32 GB of ram, solid state C: drive, and the two archive drives for videos are 2 TB each, giving it a teraquad of hard drive space. It clocks at 3.4 GHz. And its not even the latest and greatest. Supercomputers, I'm telling ya! When can I get this code?

ohiovr
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Re: New finding may explain heat loss in fusion reactors

Postby ohiovr » Tue Feb 16, 2016 7:27 pm

General Atomics owns the simplified microcode, per the article.

quixote
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Re: New finding may explain heat loss in fusion reactors

Postby quixote » Tue Feb 16, 2016 7:56 pm

Tom Ligon wrote:... two archive drives for videos are 2 TB each, giving it a teraquad of hard drive space.

If you're doing RAID, make sure it's RAID1, not RAID0. If you're not, make sure you're backing up these drives to something. Drives fail all the time. I'd hate to see you lose data.

Tom Ligon
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Re: New finding may explain heat loss in fusion reactors

Postby Tom Ligon » Tue Feb 16, 2016 9:08 pm

Yup, that's why I got a WD "My Book" drive.

The big drives are for video storage. If I lost my video archive I'd be pissed, but I doubt the world would miss it much. The Teraquad was built expressly as a video processing machine. The WD and a second portable drive are kept off-line.


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