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Comment by thomasahle | Hacker News Reader

It continues like this though:

> The low power outputs occurring inside the fusion core of the Sun may also be surprising, considering the large power which might be predicted by a simple application of the Stefan–Boltzmann law for temperatures of 10 to 15 million kelvins. However, layers of the Sun are radiating to outer layers only slightly lower in temperature, and it is this difference in radiation powers between layers which determines net power generation and transfer in the solar core.

So if a m^3 of sun core was moved to a powerplant it would generate a lot more energy.

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Not exactly. If, using your Star Trek-style transporter, you instantaneously transported a cubic meter of sun core into empty space, it would radiate a lot of power at first, but by the very fact of radiating all that power, it would quickly cool, especially if you didn't have a good way of keeping it from expanding. But even if you did have some way to contain it, it would still cool pretty fast, since it would no longer be receiving the power input of all the other core stuff around it.

> So if a m^3 of sun core was moved to a powerplant it would generate a lot more energy.

Yes, for a tiny fraction of a second as it exploded. Its pressure would far beyond what any material could withstand (and magnetic confinement does that change that, as the outward pressure has to eventually be carried by the magnet support structure).

Just to expand on that: the kinetic energy of the particles in 1 m^3 of the material at the core of the Sun is equivalent to the yield of a 5 megaton bomb. So when I say "exploded" I really mean it.

> So if a m^3 of sun core was moved to a powerplant it would generate a lot more energy.

Would it? Or would it expand into basically normal hydrogen and helium?

Provided you could keep the plasma contained in magnetic fields, it would certainly generate plenty of free neutrons to provide heat for substantial power generation.

If you let it cool, it would stop fusing. The fusion power wouldn't magically go up.

fusion halts harmlessly when conditions are unmet

Halting harmlessly is the opposite of "producing a lot more energy".

It would produce negligible quantities of neutrons.

My understanding is that neutrons are the primary component for heat generation and therefore steam and therefore energy. At low energy fusion reactions, is this not the desired outcome?

You seem to think that the outcome of an experiment is determined by desirability, not by physics. This is called wishful thinking.

Uh my counterexample is the Sun itself. Uses fusion on a daily basis to provide vast quantities of light and heat. What a fusion reactor does is it decouples the plasma superhot gravity-laden center of a sun with a magnetic field strong enough to hold tiny pockets of plasma to generate energy (once we can go straight to fusion reactions using Boron) or to generate other particles which will create heat.

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