No-go for cheap fusion?

[Adam Whistle]

> “Gordon D. Pusch” wrote:
>
>> However, far-from-equilibrium operation is extremely inefficient;
>> indeed, Todd Rider’s Ph.D. Dissertation claims to prove that any attempt
>> to operate far from equilibrium will always consume more power than it
>> generates, <http://www.ipp.mpg.de/~awc/rider.html>.
>
> Rider’s thesis is on advanced fuels, though. Is this necessarily
> the case for DT plasmas?

I don’t have a copy of Rider’s actual dissertation, just his published
papers on his dissertation work; but my understanding is that Rider’s
Dissertation has two parts, resulting in two separate “No-Go Theorems:”

1.) Any attempt to maintain a plasma in an out-of-equilibrium state will
consume more power than will be gained through an increase in the fusion
rate. This part seems to be a very general kinetic-theory argument, based
on the fact that all the relaxation times in a plasma are orders of
magnitude shorter than the fusion reaction “burn rate” timescale;
according to Rider, this argument rules out all non-equilibrium schemes,
such as Maglich’s Migma, or Bussard’s reincarnation of the Farnsworth
Fusor. (One of Rider’s papers was entirely devoted to a critique of
Bussard’s work on electrostatic confinement).

2.) Even in an equilibrium plasma, the loss rates for all “advanced”
fuels are so high that only D/T has any chance of commercial breakeven.

I am CC:’ing a copy of this posting to Arthur Carlson, who used to hang out
in this group (I haven’t seen anything from him in a while) and maintains a
webpage summarizing Rider’s Thesis at <http://www.rzg.mpg.de/~awc/rider.html>,
to ask if I am misrepresenting the contents of Rider’s Dissertation, since
I have only read Rider’s papers and various comments on the dissertation
itself.

From: http://sci-phys-plasma.caeds.eng.uml.edu/2001/11-01-012.htm

This definitely raises questions whether easy fusion using more simple and cheap methods then those used in the Tokamak can be done.
Discuss?

[Lerner]

Rider’s analysis, among other problems, does not take into account the magnetic field effect we intend to use in focus fusion, which dramatically reduces x-ray losses and allows net energy production with pB11 fuel.

[Adam Whistle]

What about other fusion attempts, if you don’t mind my disloyalty?

EDIT:
What “other” problems are there with Rider’s analysis?

[Torulf]

Bussard have also “broken” the Todd

[Falstaff]

Lerner:

Rider does address application of external fields, in that he points out that any external field cannot effect the entropy, It is the entropy that forces the x-ray loss. One can not move energy from fast ions to slow ions via the same field.

[Lerner]

The magnetic field effect reduces the electron temperature for a given ion temperature, so reduces the x-ray energy loss. It is a quantum effect and Rider does not consider it. Calculations are only as good as the physics that go into them.

The Sandia z-pinch results, where they got ion temperatures of 280 keV and electron temperatures of 3.6 keV in an iron plasma is probably an experimental demonstration of the magnetic field effect. I am still analyzing those results.

[Falstaff]

260keV vs 3.6KeV for how long? If they are collocated for any time they must eventually thermalize, and no external B field can stop that. Per Rider: Eq 3.77, pg 123

[Lerner]

About 4 ns at an ion density of 10^20/cc. If you assume no magnetic field effect, given the measured ion temperature, the electron temperature should have risen in that time to 19 keV. But the measured electron temperature peaked at 3.6 keV.

Actually, since the magnetic field effect makes ion heating of electrons far les efficient than elctron heating of ions, it allows a steady state difference in ion and electron temperatures of as much as 20 to 1. This is calculated from very standard physics and no laws of thermodynamics are violated.

[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.

[Lerner]

I’ve submitted a paper on the z-pinch results which is now being reviewed.
Our latest calcualtions indicate that we don’t have to reach 16 GG–8 GG should do it. Still high, of course, but we think we can do it with the next experiment, if it is funded.

[delt0r]

I will look forward to it.

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

[Lerner]

I am not posting it until I see what the reviewers say. But if you want to look at it, just send me your email. You can get me direct at elerner@igc.org

[Zara]

The ability to see the easy understanding of backward looking at the particles needed to mintain this sort of energy and to amplify with induction is the answer to any questions about the process. It’s almost like there is always a Capacitor there and then if you add the right Inductance then viola you have an exact match of what you need in order to understand the equation. It’s not near as easy as it sounds it’s actually one of the most advanced technologies on this planet. It is however a very viable group of scientists that can produce small scale hydrgen power plants for smaller countries and areas that are much safer and ceaner than our current ones while also pushing the industry toward hydrogen fuels which are totally harmless to the environment if done properly.

[Brian H]

Zara;
the technology is equally applicable to developed countries, with large requirements. It’s just that the sources would likely be distributed widely, rather than centrally located requiring heavy-duty long-distance transmission tech. It could seriously de-complexify the current grids.

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