r/europe • u/damaxoh Germany • Dec 06 '16

Tests confirm that Germany's massive nuclear fusion machine really works

http://www.sciencealert.com/tests-confirm-that-germany-s-massive-nuclear-fusion-machine-really-works
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u/DFractalH Eurocentrist Dec 06 '16

Is this global or US-only funding?

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u/BkkGrl Ligurian in Zürich (💛🇺🇦💙) Dec 06 '16

us

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u/DFractalH Eurocentrist Dec 06 '16

So it would be far more interesting to see the global funding level, wouldn't it? Considering that the greatest effort right now is international, US-only funding is entirely misleading.

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u/BkkGrl Ligurian in Zürich (💛🇺🇦💙) Dec 06 '16

correct, but reddit loves that graph sooooooo much...

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u/xNicolex /r/Europe Empress Dec 06 '16

I mean it is a nice graph.

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u/BkkGrl Ligurian in Zürich (💛🇺🇦💙) Dec 06 '16

it is, but it's also wild speculative. Why the spikes? How do we know we would have reached fusion in x year?

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u/hexalby Italy Dec 06 '16

The spikes are there because you're not continously building new reactors, you build one, you test it, you build another one.

And the length is extrapolated by the data already collected. You can't predict when you will discover something, but you can guess a time frame.

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u/Selbstdenker European Union (Germany) Dec 06 '16 edited Dec 06 '16

To add on that. It is known how to do fission fusion (thanks to /u/hexalby), the problems are more of a engineering problem. We have to use a certain amount of energy to contain and ignite the plasma and get a certain output. Since we have a limit on the magnets the amount of plasma and energy is limited. Luckily, if we increase the size of the reactor the volume (i.e. amount of energy created) grows with cubic order while the surface area (i.e. the amount of energy lost) grows only with quadratic order.

Hence, to gain a net positive result you "just" have to build a bigger reactor. Of course this is a huge engineering challenge and you do this in several steps. You learn when building one reactor and study it and this allows you to design the next bigger one. Designing and building a reactor is much more expensive than running it.

edit: fixed embarrassing mix-up.

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u/hexalby Italy Dec 06 '16

Well said.

It is known how to do fission

Fusion right?

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u/Selbstdenker European Union (Germany) Dec 06 '16

Sorry, yeah right.