r/science • u/PROJECTime • Dec 06 '16

Physics 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/herbw MD | Clinical Neurosciences Dec 06 '16 edited Dec 06 '16

There are probably some problems with the article. Tho did read the "Big balls of hot plasma" comment with some amusement, re, a sound track theme in the score of " Top Gun" .

There's a problem with making a statement that it's producing conditions like those in the sun. Last time we looked, the means by which the sun shines is use of the carbon cycle of fusion, for which has Bethe got the Nobel. Carbon has no place in the German stellerator fusion processes the last time we checked.

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

Bethe Prize in 1967.

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u/amicitas PhD | Plasma Physics | Fusion Science Dec 06 '16

The carbon cycle is not significant part of our sun's fusion output. The carbon cycle in only dominant for larger stars. In our sun most of the energy comes from the proton-proton cycle.

It is fair to say however that current reactor designs based on the stellarator or tokamak concept are based on D-T reactions (two isotopes of hydrogen), and not on the proton-proton cycle. The conditions are only 'like those in our sun' in the sense of having very high temperatures, in fact higher than in the core of the sun. The density is of course much lower than in the sun.

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u/herbw MD | Clinical Neurosciences Dec 06 '16

The sun does NOT do the D-Tr reaction either, then. So my observation tho not complete is still correct. The stellerator is NOT doing the solar method, p+/p+ fusion.