Helion Energy? Did they beat Tri Alpha? Scam?

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

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chrismb
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Post by chrismb »

Torulf2 wrote:Should not the ”Penning fusion (PFX, LANL)” go to ELECTROSTATIC:?
Possibly!...

I think there was more that could've been done with that experiment, namely confining the ions themselves rather tha trying to build up an electrostatic core of electrons. The reason being that the power-density of ion-ion collisions would've been way to low to get any meaningful reaction rate out of it.

There are cross-overs all through this list, and I do not intent to create strict delineations. Personally, I am on record for saying that Polywell will behave more as a magnetic trap than an electrostatic one (viz. if it works at all then it will tend towards a thermalised bunch of stuff).

Similarly, tokamaks actually behave more as beam-target devices whilst they crank up. In the short pulses that they currently manage, only some 50% of reactions are actually 'thermonuclear'.

Torulf2
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Solo
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Post by Solo »

Hmm, from what I can tell, that Russian "galatea" sounds suspiciously like polywell, in that they involve current-carrying conductors passing through the plasma, and that they are an older design that's regaining attention. I'm having trouble finding any details, though.

Torulf2
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Post by Torulf2 »


Art Carlson
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Post by Art Carlson »

This is exciting. My skeptical and experienced eye wasn't able to catch any problems. There is obviously a lot of data and thought behind the concept. It is a long row to hoe from here to a reactor, so there is still a lot that could go wrong, but this is a great start. They seem to be in a regime where MHD stability is under control, and generally do not make any dramatic extrapolations from proven results. There is a lot of prejudice in the world against high-voltage, pulsed machines - understandably - but I think it's worth a shot, especially since problems like current drive and steady-state divertor operation are also on the ragged edge of feasibility. One thing that I found troubling was the talk about a "Fissile/Fusile Breeder Reactor". This is what everybody tries if they can't quite get a decent Q from their reactor concept. It wasn't clear if this was just thrown in to reduce the projected time-to-market, or if there is a fundamental reason that the concept might not get above Q of 1 to 3. In any case, you should keep your eye on this one.

MSimon
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Post by MSimon »

Art Carlson wrote:This is exciting. My skeptical and experienced eye wasn't able to catch any problems. There is obviously a lot of data and thought behind the concept. It is a long row to hoe from here to a reactor, so there is still a lot that could go wrong, but this is a great start. They seem to be in a regime where MHD stability is under control, and generally do not make any dramatic extrapolations from proven results. There is a lot of prejudice in the world against high-voltage, pulsed machines - understandably - but I think it's worth a shot, especially since problems like current drive and steady-state divertor operation are also on the ragged edge of feasibility. One thing that I found troubling was the talk about a "Fissile/Fusile Breeder Reactor". This is what everybody tries if they can't quite get a decent Q from their reactor concept. It wasn't clear if this was just thrown in to reduce the projected time-to-market, or if there is a fundamental reason that the concept might not get above Q of 1 to 3. In any case, you should keep your eye on this one.
I'd call it more interesting than exciting. A Q of 1 to 3 is pretty poor for D-T.

With no losses (hah) a BFR burning pB11 at the resonance peak has a theoretical Q of >20.
Engineering is the art of making what you want from what you can get at a profit.

Art Carlson
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Post by Art Carlson »

MSimon wrote:I'd call it more interesting than exciting. A Q of 1 to 3 is pretty poor for D-T.
That's why the main question on my mind is what this number means. Is it a prediction or an assumption? Is it for the proof-of-concept experiment they want to build now or is it some kind of fundamental limit? My guess is that it is a near-term goal and there is no reason not to expect Q > 20 once you work out the details. I'll try to find out more.
MSimon wrote:With no losses (hah) a BFR burning pB11 at the resonance peak has a theoretical Q of >20.
The difference is that the PHD figure is based (one way or another) on dozens of published, peer-reviewed papers, both experimental and theoretical. The experimental base is large enough to derive a scaling law for confinement, and the physics theory is unfamiliar but uncontroversial. Compared to that, the knowledge base and plausibility for a BFR is (expletive deleted) poor.

chrismb
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Post by chrismb »

So, does this PHD come under my title 'Field-reversed colliding beams' for Tri-Alpha, or have I misunderstood Tri-Alpha - or either of them. This PHD scheme looks more like some hoped-for compression through a gap as the point of fusion.

Art Carlson
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Post by Art Carlson »

Art Carlson wrote:That's why the main question on my mind is what this number means. Is it a prediction or an assumption? Is it for the proof-of-concept experiment they want to build now or is it some kind of fundamental limit? My guess is that it is a near-term goal and there is no reason not to expect Q > 20 once you work out the details. I'll try to find out more.
The paragraph at the top of p.4 of Quasi-steady Fusion Reactor based on the Pulsed High Density FRC reads
Since the FRC closed poloidal flux, phi_p scales as r_s^2, it can be seen that small s requires small size even at fusion temperatures. Also in past experiments it was found that the more prolate the FRC, the larger the s value before a marked deterioration in confinement was observed. FRCs formed with s/epsilon values less than 0.5 displayed good confinement. Compression will increase the FRC elongation to ~ 20, but the observed threshold based on confinement effectively limits the FRC flux to 75 mWb or less. A flux of 25 mWb is sufficient for a Q ~ 1 fusion burn for the PHD QSFR, and well within the stability and good confinement regime. For higher Q fusion burn, more flux would be required to extend the burn time. For Q > 3 either better confinement scaling must be obtained, or a means for achieving stability at higher flux must be found. It is thought that the kinetic contribution from the helium ash may enhance FRC stability, and allow for higher flux operation. There is reason to believe that the dynamically formed translated FRC has enhanced confinement over the in situ formed FRCs used in the scaling [4]. Significant toroidal flux generation is thought to occur during dynamic formation which has been shown to stabilize rotational modes [5]. Future experiments will tell. However the true value of the FRC based QSFR may not necessarily come from the production of heat from fusion neutrons. Operation as a component test facility for a fusion DEMO, or more notably as a fissile/fusile fuel breeder, a low Q device will be sufficient and possibly even desirable.
That sounds like the answer is that it's a physics limit that won't be solved by simply making the machine a bit bigger or the field a bit stronger. On the other hand, there are also several effects that might enable an end run around this limit. Please excuse me if I remain (guardedly) excited.

On of the features of the polywell that captures the imagination of its followers is that some experiments, even if they are not on the cutting edge, can be done in the garage. Is the same true for FRCs? Mostly you need a big capacitor bank, a vacuum system, and a rugged solenoid. For diagnostics, a few flux loops should be enough to get started. It doesn't sound any worse than a polywell, and you don't have the high voltages to worry about. (Conspiracy warning: I'm planning to hijack this forum and turn it into talk-frc.)

Art Carlson
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Post by Art Carlson »

Star power:
MSNW needs somewhere between $10 million and $20 million to build its full-size fusion engine, which Slough says will be capable of producing power for the grid—unlike ITER—in 10 to 15 years. The ideal size for a fusion engine, according to Slough, is between 50 and 100megawatts. At that size, he estimates the power MSNW can produce will cost about $29 per MWh.

tomclarke
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Post by tomclarke »

What do you think of the QSFR neutron source / Thorium reactor application?

Tom

Art Carlson
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Post by Art Carlson »

tomclarke wrote:What do you think of the QSFR neutron source / Thorium reactor application?
It's like kissing through a screen door. If we have a Q=1 or Q=3 fusion machine, those applications might make sense. But it would be a big disappointment if we get that close and cannot manage to build a pure fusion power plant.

Solo
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Post by Solo »

Well, this is cool! Art is (guardedly) excited about something! :lol:

So they are planning on just shooting the plasma into a sustained high B-field region and relying on the kinetic energy of the plasma to compress itself, right? I initially thought they were going to try to ramp the compressing field (as if this were a MTF w/o the imploding liner) but that wouldn't make any sense, too energy intensive.

chrismb
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Post by chrismb »

..and there I was thinking Bernoulli predicted the pressure would go DOWN in a flow of material that is restricted...

Art Carlson
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Post by Art Carlson »

chrismb wrote:..and there I was thinking Bernoulli predicted the pressure would go DOWN in a flow of material that is restricted...
One of the things you have to get used to when working with FRCs is that it is a 2-D equilibrium. (This was one of the faults of Rostoker's CBFR concept.) When you push on the sides by raising the magnetic field, the plasmoid does not squirt out the ends but rather gets shorter due to the tension of the field lines that wrap around the ends.

That might be one answer to Bernoulli. Another could be that Mr. B. says the pressure is low where the velocity is high. The FRC is formed with a high velocity and then is shot into a confined space where it is brought to a halt. Where is has the lowest velocity is where it should have the highest pressure. It's something like conservation of energy, but you have to be sure to take proper account of the magnetic field.

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