reddit: We are nuclear fusion researchers, ask us anything

[Joseph Chikva]

If what you were saying was true, WB-8 would not have been built. That is the thing with actual hardware, it is hard to get around the reality of device operation results.

I know many devices (actual hardware) that have been built with zero results. Please show real operation results of WB8 and then please compare them with results of WB6.
Comparing you would get real numbers instead of Kiteman's juggling with numbers 8^4* etc.
If actual with real operational results, please, put those results on the table.

[mvanwink5]

You and I could just pool our money and build one, then we would have the data. A bonus would be that it would be fun. Or we could just wait like we seem to do for everything out of our hands and drink some whiskey, or vodka. EMC2 does seem to be giving it a go, and they are still in process.
Best regards

[Joseph Chikva]

You and I could just pool our money and build one, then we would have the data. A bonus would be that it would be fun.

Thank you your proposal. I sould have two things: enough money and belief in concept. And I have no neither that nor another.

[Betruger]

Neither one nor the other. Or just "neither".

[Joseph Chikva]

Neither one nor the other. Or just "neither".

Ok neither.

[KitemanSA]

8^4*1.5^3=13824 ~ 4 orders, but who's counting

You like juggling with numbers. I see two-dimensional scaling in your calculation.
That meant that:
Fusion rate is proportional to fourth degree of magnetic field
Fusion rate is proportional to third degree of geomtric dimensions
Recall that scalling law does not belong to the Laws of Nature.
Real researchers always try to avoid multi-dimensional.

From another site I found this.

Plasma Fusion Reaction Rate = R * n1 * n2
n1,n2 = Densities of reacting species (particles/m3); R = Rate Coefficient (m3/s).
Multiply by Ef to get fusion power density.

Please note that the densities are reported by most physicists to be proportional to B² and the "rate coefficient" is proportional to volume (R³)
There you have it. Rate is proportional to R³ * B² * B² ; or B^4*R^3 just like I reported.

[KitemanSA]

If what you were saying was true, WB-8 would not have been built. That is the thing with actual hardware, it is hard to get around the reality of device operation results.

I know many devices (actual hardware) that have been built with zero results. Please show real operation results of WB8 and then please compare them with results of WB6.
Comparing you would get real numbers instead of Kiteman's juggling with numbers 8^4* etc.
If actual with real operational results, please, put those results on the table.

Hey, you finally seem to be getting it. When you play with numbers (it is called making a hypothesis) it tells you nothing except what SHOULD (or MIGHT) be. That is why you do research. Hence, EMC2's contract.

So far, your "reasons" why this can't work have been dismissed by the researchers doing the work as not being an issue, while the generally accepted theory that suggests it SHOULD work has not been found wrong. This tells me the research shold continue.

As a clarification, what is most purely in question is not the power scaling, but the LOSS scaling. There is no real good description of that. But the loss scaling appears to be proportional to a factor APPROXIMATELY X^2. I've also read X^2.25. Read the Valencia paper for more info.

[Joseph Chikva]

8^4*1.5^3=13824 ~ 4 orders, but who's counting

You like juggling with numbers. I see two-dimensional scaling in your calculation.
That meant that:
Fusion rate is proportional to fourth degree of magnetic field
Fusion rate is proportional to third degree of geomtric dimensions
Recall that scalling law does not belong to the Laws of Nature.
Real researchers always try to avoid multi-dimensional.

From another site I found this.

Plasma Fusion Reaction Rate = R * n1 * n2
n1,n2 = Densities of reacting species (particles/m3); R = Rate Coefficient (m3/s).
Multiply by Ef to get fusion power density.

Please note that the densities are reported by most physicists to be proportional to B² and the "rate coefficient" is proportional to volume (R³)
There you have it. Rate is proportional to R³ * B² * B² ; or B^4*R^3 just like I reported.

That's right in case if you achieve that densities. But changing densities you change the properties of plasma and enter in "terra incognito". For example scaling in TOKAMAKs is only around dimensions and nobody from "Tok guys" try to increase density above 1-2E20 m^3.
What do you think why?
And what do you think is that difficult?
I would answer that it is not difficult. By increasing the loop voltage in TOKAMAKs from 0.5-3 V (these are real numbers ) you can easily increase density. And, yes, fusion rate is proportional to square of density.
But nobody do that. Only one dimensional scaling: increasing linear dimension they increase confinement time to up to several sec for JET and to desired 1000 sec for ITER.
Or you would like to say that anybody of Polywell guys investigated plasma behavior at 10^22 m-3? I doubt that yes.

[mvanwink5]

KitemanSA, thanks for the B^4R^3 power scaling explanation. Joseph still can't bridge the conceptual leap from Tokamaks to Polywell. Perhaps he has difficulty in reading the Valencia paper. I know I can't read Russian, so he is doing much much better than I considering he is following most of what is being said here.
Best regards

[Joseph Chikva]

Joseph still can't bridge the conceptual leap from Tokamaks to Polywell.

Scaling in fusion is very common term. And mentioned by Kiteman proportions is the first what people study when begin touching with any fusion approach not only Polywell or TOKAMAK.

[ladajo]

I was thinking about Joseph's earlier comment that WB6 made 1.5 mW of power.

I make it for 6 mW.

1*10^9 Neutrons per second
gives
5*10^8 Fusion rate (DD)
with
7.30*10^7 DD Enegry Rate/Reaction
and with
1.6*10^-19 eV/Joule
gives
(5*10^8 Fusion rate (DD)) * (7.30*10^7 DD Enegry Rate/Reaction) * (1.6*10^-19 eV/Joule)

= 0.006 Wattsec

[Joseph Chikva]

I was thinking about Joseph's earlier comment that WB6 made 1.5 mW of power.

I make it for 6 mW.

1*10^9 Neutrons per second
gives
5*10^8 Fusion rate (DD)
with
7.30*10^7 DD Enegry Rate/Reaction
and with
1.6*10^-19 eV/Joule
gives
(5*10^8 Fusion rate (DD)) * (7.30*10^7 DD Enegry Rate/Reaction) * (1.6*10^-19 eV/Joule)

= 0.006 Wattsec

...producing DD fusions at 2.5E9 fus/sec. This is 200,000 times higher than the early work of Hirsch/Farnsworth and a world’s record for such IEF devices at same conditions.

Fusion rate of 2.5E9 fus/sec for DD fuel corresponds to power 1.5 milliwatt.

2.5E9 events/sec* aprox 4E6 eV/event *1.6E-19 Joule/eV=16*10^-4 Joule/sec= 1.6E-3 W=1.6 milliwatt

[KitemanSA]

Thanks KitemanSA that is what I calculated but just misspoke.

That is what I figured.
Thank YOU for being a gentlebeing about my teasing. It is a habit of mine that annoys some to my detriment. I am very happy you took it in the friendly manner it was intended.

[ladajo]

I was thinking about Joseph's earlier comment that WB6 made 1.5 mW of power.

I make it for 6 mW.

1*10^9 Neutrons per second
gives
5*10^8 Fusion rate (DD)
with
7.30*10^7 DD Enegry Rate/Reaction
and with
1.6*10^-19 eV/Joule
gives
(5*10^8 Fusion rate (DD)) * (7.30*10^7 DD Enegry Rate/Reaction) * (1.6*10^-19 eV/Joule)

= 0.006 Wattsec

...producing DD fusions at 2.5E9 fus/sec. This is 200,000 times higher than the early work of Hirsch/Farnsworth and a world’s record for such IEF devices at same conditions.

2.5E9 events/sec* aprox 4E6 eV/event *1.6E-19 Joule/eV=16*10^-4 Joule/sec= 1.6E-3 W=1.6 milliwatt

Joseph,
Why 4.6E6 per event, and not 7.3E7?

In any event, if I redo based on 7.3E7 energy/event(DD) and 2.5E9/sec, that would be:

2.5E9 fusions/sec * 7.3E7 energy/event (DD) * 1.6E-19 eV/Joule

= .029Wattsec (29mW)

I guess that question in our difference is where you are getting your 4.6E6/event for energy produced?

[Joseph Chikva]

Joseph,
Why 4.6E6 per event, and not 7.3E7?

Two reactions occur with about equal probability.
D + D = T (tritium 1.01 MeV) + P (3.02MeV)
D + D = 3He (.82 MeV) + N (2.45 MeV)

So, from first type of reaction 4.03 MeV= 4.03E6 eV
While from the second - 0.82+2.45=3.27 MeV = 3.27E6 eV
Equal probability means that if e.g. million events occured, there will be aprox 500000 of first and 500000 of the second type. Not million times of both types so not 7.3E6 eV/event.
But average energy gain from each DD event 7.3/2=3.65E6 eV if to be correct. And not aprox value 4E6 eV as I typed for simplicity

Also, almost all tritium nuclei will react with deuterium giving 17.6MeV per event.
It is too lazyness for me now to calculate their share in balance - the day here is only beginning and I should go to work. But you will get the same order of magnitude in any case.