3 ms·

Getting things to fuse is "easy" in the sense that you can do it on the lab bench with a farnsworth hirsch fusor, but that has no hope of ever reaching break-ev

Getting things to fuse is "easy" in the sense that you can do it on the lab bench with a farnsworth hirsch fusor, but that has no hope of ever reaching break-even. This article doesn't talk about break-even potential at all and yet they jump to potential applications.

petermcneeley 6y ago
"In the latter case, that extra neutron can start the process over again, allowing two more deuterons to fuse." So sounds like they are hoping for free reactions.
- the8472 6y ago
  That's future research and doesn't necessarily mean it makes up for losses. They're counting chickens before they hatched.
strbean 6y ago
That still involves heating though, right?
ramraj07 6y ago
Is breaking even in such an experiment in violation of any thermodynamics laws? Or is it that we just haven't figured it out?
- leephillips 6y ago
  It doesn’t violate thermodynamics; it’s the conversion of mass to other forms of energy. Nuclear fusion is the source of energy from the sun, but the sun has the advantage of its enormous gravity keeping things confined. The attempt to extract usable energy from controlled fusion on Earth is the attempt to, in the absence of this helpful gravity, find some other way to get enough nucleons close enough together. Nature makes this practically impossible, which is why we don't have fusion power after 70 years of trying. Fortunately, we don’t need it, as we can now use the sun’s fusion here on Earth.
- xenadu02 6y ago
  In theory anything lighter can fuse toward Iron. Anything heavier can fission the same direction. Splitting or fusing Iron requires input of energy even in theoretical scenarios at 100% efficiency. In practice a great many nuclear reactions are not chain reactions or don't yield enough energy to be useful. Really large atoms kinda want to fission due to the speed of light: forces can't propagate from one side to the other fast enough to completely balance out. So splitting Uranium is a lot easier to make useful because we have a head start as it were... if you leave it alone in a box some of it will go ahead and split in pieces for you for free. Fusion is just more difficult. If you leave hydrogen atoms confined in a box approximately none of them will spontaneously fuse to form helium.

petermcneeley 6y ago

"In the latter case, that extra neutron can start the process over again, allowing two more deuterons to fuse." So sounds like they are hoping for free reactions.

the8472 6y ago
That's future research and doesn't necessarily mean it makes up for losses. They're counting chickens before they hatched.

strbean 6y ago

That still involves heating though, right?

ramraj07 6y ago

Is breaking even in such an experiment in violation of any thermodynamics laws? Or is it that we just haven't figured it out?

leephillips 6y ago
It doesn’t violate thermodynamics; it’s the conversion of mass to other forms of energy. Nuclear fusion is the source of energy from the sun, but the sun has the advantage of its enormous gravity keeping things confined. The attempt to extract usable energy from controlled fusion on Earth is the attempt to, in the absence of this helpful gravity, find some other way to get enough nucleons close enough together. Nature makes this practically impossible, which is why we don't have fusion power after 70 years of trying. Fortunately, we don’t need it, as we can now use the sun’s fusion here on Earth.
xenadu02 6y ago
In theory anything lighter can fuse toward Iron. Anything heavier can fission the same direction. Splitting or fusing Iron requires input of energy even in theoretical scenarios at 100% efficiency. In practice a great many nuclear reactions are not chain reactions or don't yield enough energy to be useful. Really large atoms kinda want to fission due to the speed of light: forces can't propagate from one side to the other fast enough to completely balance out. So splitting Uranium is a lot easier to make useful because we have a head start as it were... if you leave it alone in a box some of it will go ahead and split in pieces for you for free. Fusion is just more difficult. If you leave hydrogen atoms confined in a box approximately none of them will spontaneously fuse to form helium.