# Question of Sound Fusion Power Generation

1. Apr 15, 2006

### scorpio_wan1945

1.with the hot and cold fusion under experiment level now, would power from sound fusion provides equal or more power and economic value if it has been successfully researched?

2. what is the difficulty faced in building a commercial sound fusion generator?

3. Future of sound fusion development?

2. Apr 15, 2006

### Rach3

Sonofusion has never been observed.

3. Apr 15, 2006

### Morbius

Scorpio,

Neither "sound fusion" nor "cold fusion" has been conclusively demonstrated; and
based on our current understanding of the physics - they won't be.

Dr. Gregory Greenman
Physicist

4. Apr 15, 2006

### Astronuc

Staff Emeritus
I know 'cold fusion' was dismissed as false, but I thought that some folk from RPI and one of the labs had detected neutrons in a deuterated liquid (acetone or something). Has that been found to be false?

Here is press release from RPI - New Sonofusion Experiment Produces Results Without External Neutron Source
http://news.rpi.edu/update.do?artcenterkey=1322&setappvar=page(1)

5. Apr 15, 2006

### Azael

Taleyarkhan must be celebrating now!! I hope that experiment will be verified by another team.

Astronuc do you think sonofusion can be a viable energy source in the future??

6. Apr 15, 2006

### Astronuc

Staff Emeritus
Not as an energy source. May understanding is that the process is inherently low energy density.

7. Apr 15, 2006

### ZapperZ

Staff Emeritus
8. Apr 17, 2006

### Azael

9. Apr 17, 2006

### Azael

(if it works) is there anything preventing scaling it up?
My naive thought would be that if its possible to get one stable bubble why not thousand stable bubbles. If it is possible to scale up the number of stable bubbles in one canister wouldnt it be possible to get enough for heat production

The other option I could think of is to make the canisters very small(maby spherical canisters a few milimeters in diameter) and have alot of them in close proximity. I dont know if its possible to create a stable bubble in the frequence range required in very small canisters though?

10. Apr 17, 2006

### Astronuc

Staff Emeritus
My feeling is that at the moment, the sonofusion system uses more energy than it produces. I don't see how it could be scaled up to be a useful energy source. Using sonofusion simply for a source of neutrons would be impractical with regard to power generation.

Also, I would like to acknowledge ZapperZ's post regarding the dispute over the validity of sonofusion. It appears that, like cold fusion, sonofusion may not be proven.

11. Apr 17, 2006

### Staff: Mentor

Slight clarification - there is a difference between getting it to work and getting it to produce a positive and continuous amount of power. Regular hot fusion "works" - just only for a fraction of a second and without producing excess power (afaik).

So scaleability isn't the only issue, even if fusion can be successfully/repeatably demonstrated in a lab.

12. Apr 17, 2006

### Astronuc

Staff Emeritus
Hot fusion has been in the works since the 50's. It is the basis of thermonuclear weapons, which however, are not practical energy sources.

Seriously, fusion research has focussed on magnetically confined plasmas, which are really 'hot' and inertial confinement. Both are still in the experimental stages.

Cold fusion was found to be false, and it would appear sonofusion may also be false. Even IF sonofusion has been demonstrated, it seems limited to provided low level neutron sources. The question is whether or not it is any better than current (alternative) neutron sources.

13. Apr 17, 2006

### Azael

I hope that, even if Taleyarkhan is proven to be a crank regarding sonofusion, research into sonoluminescence will continue. Its a exciting phenomenon and maby something worthwhile will be the result of it all.

I sure enjoy the tan the big thermonuke in the sky gives me each summer

14. Apr 17, 2006

### Astronuc

Staff Emeritus
Well, yeah! Nature has demonstrated hot fusion on a big scale for billions of years, and some think that solar energy/power (PV or otherwise) is the best utilization of fusion energy, and it probably is.

15. Apr 17, 2006

### Azael

But solar power isnt exciting :yuck:

16. Apr 17, 2006

### Astronuc

Staff Emeritus
Au contraire, mon ami.

2006 IEEE 4th World Conference on Photovoltaic Energy Conversion
http://www.wcpec.org/ in Hawaii no less. :rofl:

17. Apr 18, 2006

### Azael

They sure are good at picking locations atleast :tongue2:

18. May 11, 2006

### ZapperZ

Staff Emeritus
19. May 11, 2006

### Astronuc

Staff Emeritus
Accidentally? Careless more like it.

There is such a concept as quality control, even for research experiments and laboratory measurements, which is essentially just good scientific or engineering practice, or something like due diligence (i.e. attention and care).

In the nuclear industry, QA/QC is mandated by 10 CFR 50 Appendix B!

Not necessarily. It's comments like this that really bothers me about media, even scientific journals.

Last edited: May 11, 2006
20. May 15, 2006

### vanesch

Staff Emeritus
Just some information concerning the detectors. I'm surprised to read some explanations given by the team.

BF3 gas detectors are quite good (but extremely dangerous) neutron detectors - I fail to understand the comment about them seeing gamma radiation, because they essentially don't, and moreover the signal they produce in a BF3 detector is extremely weak and difficult to distinguish from the electronic noise.
The thermal neutron interaction in BF3 liberates more than 2.3 MeV, which is a rather strong signal ; electrons liberated by gamma radiation usually deposit much less energy in the gas before hitting the wall, hence the very strong separation between neutron and gamma signals.
The polyethylene around a neutron detector works essentially as a moderator in order to slow down fast neutrons. As the absorption cross section of the B in the detector essentially goes down linearly with neutron speed, this is done to increase the efficiency of the detector setup for fast neutrons (by slowing them down first before having them interact with the detector). But normally, polyethylene is NOT generating any gammas under neutron irradiation ! So I don't understand that comment.

However, a LiF detector is highly sensitive to gamma radiation. In fact, it is almost a better gamma detector than a neutron detector and it is difficult to distinguish both signals. Again, however, the polyethylene doesn't generate gamma radiation.

Normally, all this shouldn't be an issue, when calibrated against a known lab neutron source.

However, there's a main worry with such setups, which is electromagnetic interference. Detectors which are badly cabled up can easily mimick particle detection, while what they are in fact seeing is electromagnetic disturbance from a nearby appliance.

21. May 15, 2006

### ZapperZ

Staff Emeritus
So vanesch, what is your gut feeling about Taleyarkhan's claim in all of this, knowing the type of measurement he claim to be doing?

I only have some superficial understanding of his detection scheme, so I can't really judge the reasonableness of his result. However, based simply on the history of this thing and what has transpired, there are just way too many red flags appearing one after the other that just simply don't sit right. Usually, claims this significant are tested and reproduced very quickly (after all, it isn't that outrageous of an experiment to do). I see nothing of this sort at all. This almost mirrors the Schon debacle, except that in the latter, there were only whispers in the hallway that no one could reproduce the results at the very beginning.

This one, on the other hand, is splattered all over the media.

Zz.

22. May 15, 2006

### Astronuc

Staff Emeritus
Without a detailed schematic and description, it is hard to understand how Taleyarkhan and his colleagues used the gamma and neutron detectors.

As for gamma radiation (~0.48 MeV), it does come from the decay of 7Li* which is produced in approximately 94% of (n, $\alpha$) reaction with 10B. But it is not clear that is what they were doing.

http://scitation.aip.org/getabs/servlet/GetabsServlet?prog=normal&id=PLEEE8000069000003036109000001&idtype=cvips&gifs=yes [Broken]
Phys. Rev. E 69, 036109 (2004) (11 pages)

Last edited by a moderator: May 2, 2017
23. May 15, 2006

### Astronuc

Staff Emeritus
The goal in fusion is to provide sufficient energy to the nuclei to cause them to fuse, reconfigure, and release the binding energy in the form of kinetic energy of the product nuclei.

In magnetic confinement, this is done by heating light nuclei (usually isotopes of hydrogen) to several million K, such that the atoms are ionized and the nuclei will collide such that eventually they will fuse. One method of heating is neutral beam injection in which some atoms are stripped of electrons, accelerated, recombined with electrons just before they hit the plasma, and then are ionized by collisions with the plasma. Neutral beam energies are on the order of 80-100 keV, for D atoms.

Accelerators are typically not used. (In response to a post which was deleted)

In inertial confinement, a very small target capsule of fusile material is hit with high energy lasers which heat an outer ablative layer. The ablation cause the capsule to be highly compressed which causes rapid heating to several million K, and fusion takes place, and the capsule burts in a pulse of energy.

Sonofusion is questionable at the moment. One can read about it in Phys. Rev. E, which I cited. The authors claim about 100 million K in the collapsed microbubbles. I'd have to read the article to learn how they determined that.

Last edited: May 16, 2006
24. May 16, 2006

### Morbius

Astronuc,

Instead of using lasers, like at Lawrence Livermore; the "other" method of inertial
confinement fusion is to use the "pulsed power" devices like the Z-Machine at
Sandia National Laboratories:

http://www.sandia.gov/media/z290.htm

Picture of the Z-Machine firing:

http://www.sandia.gov/media/images/jpg/Z02.jpg

Although termed an "accelerator", the Z-Machine doesn't accelerate the fusion fuel.
Instead it dumps a hugh amount of electricity through a target made of fine wires:

http://www.sandia.gov/media/images/jpg/Z01.jpg

The wires magnetically implode the fusion fuel - similar to the way
the laser-driven ablation implodes fusion fuel in laser fusion.

Dr. Gregory Greenman
Physicist

Last edited: May 16, 2006
25. May 16, 2006

### Astronuc

Staff Emeritus
Morbius,

I was thinking about electron beams and perhaps Z machine, but I don't know where they are in comparison with other methods. At the moment, the Z-machine is producing lots of X-rays with temperatures of the wire ~1.6 million K (or about 140 eV). They need about 100 times that amount IMO - 14 keV (160 million K) for any reasonable attempt at fusion.

I wonder when they will get there?