[sodaclean]

Sonoluminescence is not power positive. Fusion would be trivial to prove with a neutron detector- so saying "theres debate" is arguably dishonest.

Sonoluminescence is weird and awesome enough as is: cavitation that produces light.

[akshatjiwan]

Researchers have reported neutron detection but these results have not been reproduced and some scientists have attributed this detection to 'noise'. Bubbles are tiny they have very small amount of gas in them so detecting that is not exactly straightforward... I think

for example a in a 1um radius bubble the total mass of gas would be ~ 10^-18kg.

Personally I doubt fusion occurs inside bubbles. Even if we take the highest reported temp 30000K that's way below what's required for fusion.

Also bubble literature is full of fantastic claims—one that comes to mind is assertion that pressures of around 10Gpa can be generated which seems highly improbable because that's likely to induce phase change in the fluid.

However it's quite possible that I'm wrong. Because bubble science keeps on throwing new surprises.

[sodaclean]

Are you agreeing or disagreeing with it being trivial to check if theres fusion?

> However it's quite possible that I'm wrong. Because bubble science keeps on throwing new surprises.

Ultimately that's my assertion. No need for exaggerated/optimistic claims when something interesting turns up about it on a regular basis.

[akshatjiwan]

I'm disagreeing that it's trivial to check for fusion because of low mass of gas inside the bubbles and suggesting that it's unlikely that fusion would ever happen in a bubble because temperatures required for fusion are way higher than bubble cavitation temperatures.

Do you have any ideas on how detection can be made in a bubble radius of say 100um?

In laser fusion experiments the pellet size is in mm range and it's completely filled with solid/liquid hydrogen to achive high particle density.Thats not possible in a bubble.

The thing is even for something as well studied as sonoluminescence there is no scientific consensus. Literature is all over the place when it comes to bubble gas temperature during cavitation.

Lots of arguments and debates are ongoing in the community. I think that's what happened with fusion story.

[sodaclean]

https://en.wikipedia.org/wiki/Neutron_detection

[Ekaros]

Wouldn't fusion also mean net energy generation? Or at least much higher than inputs... So there should be lot more energy in system than expected.

[sodaclean]

Unfortunately, no- while atoms fusing has a fixed mass to energy conversion... getting them close enough that they'll fuse takes a lot of energy. The three hurdles to effective fusion are: 1) getting more energy from fusion than was spent making it happen 2) extracting the extra energy 3) (this never gets covered) avoid neutron flux turning the whole thing into radioactive scrap before it can pay for itself and storage.

National ignition facility (NIF) recently got exited about more energy out than they put in. They don't have a plan for #2 or #3- but as a research facility focusing on #1 thats OK.

Numerous tokamak designs try to handle #1 and #2, but handle #3 by putting rails into the reactor for robots to replace and repair things.

I'm very pessimistic about #3- nothing is immune to neutron damage from fusion, it's just engineering it to fail in a way thats useful. And, once the public accepts the problem, produces less nuclear waste than fission.