Fusion reactions in nanomachines

[raeleen]

Hi everyone! I really like nanotechnology and I really want to know how biological systems could help create a new ecosystem of nanomachines!

 

I wonder about power. Specifically, could nanotech systems do a better job of tapping nuclear power than macroscale systems?

 

I have read about the National Ignition Facility and using lasers to create fusion. Would it be possible to build a device much smaller than NIF which uses nanolasers fuse individual nuclei of fusionable (please excuse if that's not a word!) isotopes?

 

How big would such a nanomachine have to be and what parts would it need? Would you use lasers, electromagnetic fields, or something else? How would you collect the energy the reaction produces and make it useful?

 

I am thinking of nanoscale fusion as a way to produce power for other nanomachines, not the entire power grid! So the amounts of power would be very small, but you'd be using that power for very tiny machines. I am not asking how you could replace a large scale plasma fusion reactor.

 

I am afraid my knowledge of physics is limited so sorry if there's anything in my question that's wrong or doesn't make sense. Please ask me if you want clarification! This is pie in the sky stuff. I don't care about what is practical today. I care about what is possible.

[Ludwik]

What do you mean by a "nanolaser"?

 

You wrote:

"I have read about the National Ignition Facility and using lasers to create fusion. Would it be possible to build a device much smaller than NIF which uses nanolasers fuse individual nuclei of fusionable (please excuse if that's not a word!) isotopes?:

 

All isotopes are fusionable but the coulomb barrier, preventing fusion, increases with the atomic number.

 

Ludwik Kowalski (see Wikipedia)

[John Cuthber]

It's a scaling problem.

Fusion reactors the size of stars are easy. Fusion reactors (of any decent output) the size of cathedrals a re just about possible and you want one that's too small to see?

Good luck.

[swansont]

The scaling issue is probably most important; overcoming the Coulomb barrier doesn't change, so the temperature required doesn't scale. But all that aside, I don't know that "nanolasers" are even possible. The amount of amplification is related to the number of atoms or charges (for semiconductor) available in the system. It stops the possibility lasing at some point as you scale the size down.

[raeleen]

Hi everyone, sorry! I don't know much about quantum physics.

 

So what you're saying is fusion works well at large scales but not so much at the nanoscale. Ok.

 

I didn't know a nanolaser is impossible! I just assumed it was.

 

I guess I will abandon my hopes for fusion-powered nanorobots

[raeleen]

So can I make the question more general, since there seem to be some smart physics types here?

 

How would YOU make a power source for nanomachines? Imagine you have the ability to build whatever you want at the molecular or atomic level. What would you use?

[wright496]

You can use chemical power or even ambient thermal energy to power them just fine.

[mississippichem]

There are molecular propellers:

 

 

The one pictured here works by attaching aromatic rings to a carbon nanotube in a chiral [non-symmetric] propeller like configuration. The aromatic rings are hydrophobic and repelled by polar water molecules causing the nanotube to rotate. I'm not sure if anyone has derived usable power from something like this used as a turbine, but I know people have observed actual work (work in the strict physics sense) being done on the nanomachines themselves by phenomena like this.