The race is on, Polywell vs Focus Fusion

[chrismb]

chris,

There are literally tens of millions of dollars floating around looking for a viable small fusion experiment that could lead to a working power plant. I have been approached more than once in the last year by folks with various levels of seriousness. Several of them with the capability and expertise of putting a billion or two into ramp up of production if the experimental results are positive.

If the Focus Fusion folks are not getting the support they want I will assume it is because some one sees a fundamental flaw.

I see two. Electrode erosion and the size (in GW) of an economically viable plant burning pBj.

Are we agreeing, or disagreeing...or other?

Millions has already been sunk into DPF since Filipov (another Kurtchatov venture of the 60s, as per tokamak) started cranking up his experiments.

Lerner has added a twist and is [in my opinion] speculating that this will give additional efficiency. I agree with your points fully. My point is that it is 'so far, so good' but the flow of money for DPF has silted up due to little to show for 50 years and Lerner has the task of un-silting that. I'm not saying it will work, what I am saying it scores stages above Polywell because DPFs are know to produce copious thermonuclear fusion reactions during operation, which cannot be said for Polywell at this moment in time.

[MSimon]

I'm not saying it will work, what I am saying it scores stages above Polywell because DPFs are know to produce copious thermonuclear fusion reactions during operation, which cannot be said for Polywell at this moment in time.

Fusors produce fusion reactions and are well known. The question is: efficiency. Polywell is supposed to solve the efficiency problem.

Focus Fusion may generate more fusions per pulse currently. However, I see the difficulties of turning it into a viable power plant as much more daunting.

Take a capacitor bank. 1,000 joules for $400 (surplus). 1 Mj for $400,000. 1Gj for $400 million (BOE estimate - capacitors used at 70% of rated voltage)

And then you need a power supply to charge those suckers. A 1 MW supply gives you a shot every 20 minutes. A 100 MW supply (a shot every 10 seconds) is going to cost you $100 million. And you had better be buying your electricity off peak.

Any way my point is that an FFR is going to be tougher engineering wise.

BFR scaling is way more tractable.

[chrismb]

Fusors produce fusion reactions and are well known. The question is: efficiency. Polywell is supposed to solve the efficiency problem.

So we're back to the nugget of whether Polywell is a fusor or not, if you're relying on the fusing-reaction-capability of a fusor to demonstrate the projected capabilities of Polywell [are a match for DPF's proven capability].

Either it's a fusor or it's not: If it is a fusor, then remember that the fusor has been discarded as anything but an experimental tool. If it is not a fusor, then you cannot rely on claiming fusors 'do' fusion reactions to show that Polwell does.

[MSimon]

Fusors produce fusion reactions and are well known. The question is: efficiency. Polywell is supposed to solve the efficiency problem.

So we're back to the nugget of whether Polywell is a fusor or not, if you're relying on the fusing-reaction-capability of a fusor to demonstrate the projected capabilities of Polywell [are a match for DPF's proven capability].

Either it's a fusor or it's not: If it is a fusor, then remember that the fusor has been discarded as anything but an experimental tool. If it is not a fusor, then you cannot rely on claiming fusors 'do' fusion reactions to show that Polwell does.

Chris,

It is a fusor. The grid is shielded.

As Richard Hull (of Fusor Net) likes to say. "Fusion is easy. Net power is hard."

As you point out there are many questions even so. Are we seeing beam-beam reactions? Are the Bremss losses tractable? What is the e fold time for thermalization? etc.

[chrismb]

Chris,

It is a fusor.

So it comes into the category of being discarded as anything but an experimental tool?

[tomclarke]

Fusors produce fusion reactions and are well known. The question is: efficiency. Polywell is supposed to solve the efficiency problem.

So we're back to the nugget of whether Polywell is a fusor or not, if you're relying on the fusing-reaction-capability of a fusor to demonstrate the projected capabilities of Polywell [are a match for DPF's proven capability].

Either it's a fusor or it's not: If it is a fusor, then remember that the fusor has been discarded as anything but an experimental tool. If it is not a fusor, then you cannot rely on claiming fusors 'do' fusion reactions to show that Polwell does.

Chris,

It is a fusor. The grid is shielded.

As Richard Hull (of Fusor Net) likes to say. "Fusion is easy. Net power is hard."

As you point out there are many questions even so. Are we seeing beam-beam reactions? Are the Bremss losses tractable? What is the e fold time for thermalization? etc.

We have (works <==> net power):

Polywell - highly attractive but unproven and questionable scaling laws, if it works engineering considerations look difficult but possible.

FRC - much less attractive scaling laws but more proven, if it works engineering considerations look good.

DPF - lots of questionable issues about scaling. I am not sure whether there are really attractive unproven scaling laws, since there seem to be unresolved issues about increasing current - but maybe I am wrong. Engineering issues, if net power possible, look very difficult.

Perhaps I am wrong about relative difficulty of engineering issues.

In all cases there is strong chance of undesirable effects at high energies reducing output over what low power scaling laws would indicate. (Bremm - maybe other stuff).

All three are perhaps worth pursuing as long-shots? Though other than having good PR I am not quite sure what DPF has going for it compared with the other two.

Tom

[TallDave]

Once they get the electrode erosion problem in hand all should be peachy. Did you see the after pictures of a 1 MJ set up that had been pulsed quite a bit?

I'm always surprised people don't immediately look at this and say "How the hell can this design produce 100MW for any length of time?" No electrode can survive those condition for very long. It looks like a classic unobtainium problem.

It is definitely a few stages ahead of Polywell in their respective games.

Ha, no. Focus fusion has very basic scaling and continuous operation problems. Polywell is being seriously evaluated for a U.S. Navy-funded follow-on demonstration reactor if the current iteration works as hoped.

Don't confuse money spent with progress. We may have spent tens of billions on tokamaks, and have a net power design in (halting) progress, but they are behind Polywell in terms of a path to commercial applications.

Either it's a fusor or it's not: If it is a fusor, then remember that the fusor has been discarded as anything but an experimental tool.

Lots of things have gone from experimental tools to extremely useful technology.

[MSimon]

Polywell - highly attractive but unproven and questionable scaling laws

Actually the scaling laws - power - are straight out of standard physics. The unknown/shaky laws are the loss laws.

[chrismb]

Ha, no. Focus fusion has very basic scaling and continuous operation problems.

Ha, yes. Are you really suggesting that if fusion experiment A produces fusion neutrons and fusion experiment B does not that experiment A is not ahead of B??

Either it's a fusor or it's not: If it is a fusor, then remember that the fusor has been discarded as anything but an experimental tool.

Lots of things have gone from experimental tools to extremely useful technology.

But maybe not after it has been discarded as an experimental tool. Name an experimental tool that has been studied and experimented on for 50 years to improve it, without any practically demonstrated improvement whatsoever, but that then goes on to be useful. Name it.

[MSimon]

chrismb,

Neutrons are not the holy grail nor the sine qua non of fusion research preparatory to design of a power reactor.

We do know that fusors produce neutrons (probably beam background) and that Farnsworth produced a lot of neutrons.

So at minimum we can say that the device is capable of producing neutrons if configured similarly to already successful devices. Now we know WB-6 produced some neutrons. WB-7 was to replicate a slightly improved WB-6. EMC2 is now on to WB-8 with WB-9 in the preliminary design stages.

[MSimon]

But maybe not after it has been discarded as an experimental tool. Name an experimental tool that has been studied and experimented on for 50 years to improve it, without any practically demonstrated improvement whatsoever, but that then goes on to be useful. Name it.

The steam turbine. About 1700 years in development.

[chrismb]

But maybe not after it has been discarded as an experimental tool. Name an experimental tool that has been studied and experimented on for 50 years to improve it, without any practically demonstrated improvement whatsoever, but that then goes on to be useful. Name it.

The steam turbine. About 1700 years in development.

I'm not sure I'm aware of anyone really trying to develop it to a given purpose at any stage during those 1700 years, and when they did in the Victorian age it became an instantly useful machine. Maybe I'm wrong on that, or deviating because my concern is that the presumption Polywell will even do fast-fast fusion is not demonstrated by the fusor if only because a fusor is 8 to 9 orders of magnitude below a required energy pay-back. As I allude to every now and again, showing that you can oxidise an iron nail in water doesn't demonstrate you can make a jet engine (which is also a device that oxidises a substance and differs in reaction rate by some 9 orders of magnitude).

You know that I wish Polywell well in its currently planned stages (as I give my support, in principle, to all such scientific studies without prejudicial bias) and we all look forward to it gaining traction by publicised proof of functionality [as intended] but [on the subject of this thread] DPFs have to be given a higher credit than Polywell at this time due to the absolute fact that it has been demonstrated to perform thermonuclear reactions. Turning to a different device with a performance 9 orders of magnitude below that which will be expected of Polywell does not (and I do not see can) Polywell demonstrate!

[MSimon]

chris,

Rick seems pretty confidant (of at least getting a yes/no answer) in the near term:

http://powerandcontrol.blogspot.com/200 ... ptics.html

My guess is that he is probably well into the yes camp. Otherwise why not go back to his Los Alamos job of extending POPS?

The only exotic thing about such a reactor - if it works - is the energy collection mechanism. If the energy comes out in bursts (I expect in the 100 KHz range) coils might work as an energy collector. That might make the whole unit fairly compact.

OTOH if electrostatic converters are the way to go then compaction may be a trick.

[Betruger]

Otherwise why not go back to his Los Alamos job of extending POPS?

To clearly define the impasse so that no one falls for it? Not that that's my hunch either.

[chrismb]

Otherwise why not go back to his Los Alamos job of extending POPS?

Because he is currently his own boss, driving his own ideas, in a field that (however probable or otherwise of success) will be world-changing. You feel on top of the world in those circumstances. Why would he go back to more mundane reasearch?

The only exotic thing about such a reactor - if it works - is the energy collection mechanism.

Plus the material capacity to tolerate the enormous total amount of energy output, charge flux and enormous demands on a vacuum system that would occur in the net-power output scaled version. In fact, in many analogous ways to the problems raised for DPF?

I will make a 'half-prediction'. Not one that I'll bet on but one to make a point:

The first successful net-energy fusion device will have to evolve from design prototypes by the scaling down of input energy, not from the scaling up of output enery.

I am basing this purely on a view of actual fusion research work to date, not on a theoretical preposition, such that all previous projects seem to hunt ever higher extrapolations of outputs and always seems to spiral up into seemingly impossibly out-sized devices, be it dimensional, containment or material issues. Indeed, perhaps the only sustaining net-energy fusion mechanisms need to be astronomical in size?!!

I am imagining that this would mean the first net-energy fusion devices will output in the order of milli or micro watts, so the input power will have to also be microwatts input. Maybe 1uW per device cc is the absolute limit for fusion, as demonstrated by stars, in which case fusion power is a fool's errand as it will never quench human's insatiable demand for energy.