[delt0r]

Well the vac chambers we had, we always puled them apart and gave them a reclean. We needed 10^-8 to 10^9 torr, so even a fingerprint was a disaster. Mostly turbo pumps. We at least know of no short cuts. Oh everything was bake-able to 200C IIRC and it was days for a full pump down. But then you don’t need to go that low do you? At any rate high quality vacuum is a PITA.

[delt0r]

I now work in Evolutionary biology (was physics). I assure you its not as good as you think. In fact if you understand whats going on, there are often simple things you can change for improvements that a mutation selection thing never gets. For example solar cells are far more efficient that photosynthesis.

First seek to understand….

[delt0r]

*shock* waves travel faster than the speed of sound. Often many time faster. The general Idea of GF is magnetic target fusion. The idea has many merits and sits somewhere between magnetic confinement and internal confinement. If i was going to bet on a dark horse to win the fusion race, it would be GF. There are some papers around too if you look around. Don’t have my references handy.

[delt0r]

I am very familiar with HIF. However considering that it never got close to fusion, and was only really experiment will on a small scale, his assertion that it will “just work” is weak. That’s what I mean by details. The details that matter for a *working* fusion plant. Not just one that “could” work “maybe” and by the way just give us 10billon.

[delt0r]

Very devoid of any details. I having fusion will be cool. I want to *how* to do it.

[delt0r]

Lerner wrote: No, friends, the DT logic is not right. The fraction of DT that gets burned depends on the density. When we can detect DT neutrons (not so far in this experiment) we can use the DT/DD fraction to measure the density.

I sorry but i don’t follow. So you are saying that we assume that the T produced from DD fusions are typically not subsequently burnt, or that because you don’t detect DT neutrons, that we then make the assertion?

If the T produced from DD reactions are confined I would assume they would fuse quickly since the cross section is so much higher even at 150KeV. If this is not the case, why not?

[delt0r]

The *branching* ratio is 50/50 to about 10e-5 accuracy. This is predicted from the standard model and verified by a *lot* of experimental evidence. You can learn the standard model, and atomic models yourself if you don’t believe it, you don’t even need to go that advanced in the theory in fact. Remember for atomic models (strong force) 150KeV is not really that much hotter than 1KeV. Note we are not talking about the fusion cross section (reaction rate) that’s dominated by tunneling and the electric force, we are talking about the branching ratio “after” a fusion event that’s dominated by the strong force.

There is the DD-He4+2gamma, but this is extremely rare. You must have 2 gammas to conserve all the relevant quantum numbers. So you end up with a fine structure constant squared in the branching ratio and thus you have 50-50 for DD->T+p and DD->He3+n with almost zero contribution from DD->He4.

It may gain some temperature dependence when you get to the 1GeV per nucleon and higher ranges. But probably not. Since the *fusion* branching ratio is still via the same process (you form a He4* intermediate).

[delt0r]

The branching ratio is not temperature dependent for DD fusion, its always 50-50 (its a standard model thing). Also its generally assumed that all the T produced is then burned at the rate its produced (about 10-100 times higher cross section) and this gives a 14MeV n (so half the neutrons have about 14MeV the other half about 2.5 MeV). However people generally differed on how much of the He3 is then burned. Often the approximation that no He3 is burnt at all.

I still don’t follow your numbers. Why do you triple your 13.3J? And why do you assume that Boron H yield is so much higher? Even at optimal temperature the cross section is many times lower than DD, or even DHe3.

[delt0r]

Your numbers seem off. Even with DT fusion (ie 14MeV neutrons) 3.4e13 neutrons is only about 76J of neutrons. With DD that goes down to less than 50J giving a total fusion yield of less than 100J. This is assuming a full DD burn (DD->He4, H,n).

[delt0r]

Well lets be clear. Its not really easy, and you are not really talking about a “neutron” source as per the link above.

For example 1 watt of neutrons from DD fusion with full T and D burn gives about 25,000 years to convert 1 mole of U238 to Pu239. This assume a 1 to one neutron usage and yield. This could be bumped up with some Li neutron breeding. But not much I don’t think. So you are going to need many kW of power in neutrons alone. This pretty much means that the DD fusion reactor will need to be at break even or better in practice.

Also I said is easy to separate in quotes for a reason. Its easier than separating U235 from U238. But its quite difficult to do without killing personal and generally making quite a mess.

It should be noted that the controls on depleted U is quite a bit more lax than natural U. Th is even less controlled. Americas insistence on using depleted U for armor piercing rounds notwithstanding, its likely that getting a few 10s of kg’s of U238 would be quite easy.

But I stand by my original claim, that something that can fuse B11+H (really really really hard) will work well with plain old DD (just really hard), and pose a proliferation risk. However this is quite a minor risk compared to say a fission reactor. Permits and inspections that suffice for lots of controlled legal “radioactive” facilities would be applicable here. (ie Co60 for various uses such as UHT milk production).

The biggest problem would still be NIMBY.

[delt0r]

Unfortunately anything that’s going to burn B11 and H can also burn plain old DD. Now i have a high intensity neutron generator. Any high neutron generator is a proliferation risk, since both Th and U can be converted to usable bomb materials, and in a way that make separation “easy” .

[delt0r]

I will look forward to it.

I couldn’t find it on the preprint archive :(. Oh well…

[delt0r]

I do agree that no laws of thermodynamics are violated. Also unlike Bussard IEC device there is a clear reason why it might work where Rider claims it may not. ie The Rider Thesis is not just swept under the carpet.

To this end I think that publishing something from the Z machine that shows the magnetic field effect would be very interesting in itself. If no such effect can be seen then I hope theres a good explanation. Perhaps some parameters of the Z machine can be altered to emphasis the magnetic effect. I do recall a difference in ion/electron temperatures (also in MAGPIE IIRC), so a explanation would be great.

However I still doubt that >=16GG is really achievable. Thats a really strong field, and to be perfectly honest I don’t really buy the experimental evidence of 0.4GG as achieved without more experimental collaborating evidence.

Either way though, DD or even D He3 don’t need a magnetic field effect, so even if you just get close with this approach, your home free with other fuels.

Personally I think this is our best hope so far for *economical* fusion (Though with traditional fuels). ITER might work, but i don’t think *anyone* will be able to afford that electricity.

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