Isaac Asimov's predictions 50 years on

Re:Isaac Asimov's predictions 50 years on by sergiosgc on Tuesday April 22, 2014 @08:21PM (#7631324)

I can easily concede that NIF results are too recent and still under scrutiny. However, JET's peak output was 65% of input, and these are results solid enough to justify scaling JET up with the ITER project. 65% is on the same order of magnitude, not four orders of magnitude away.

Reference:http://en.m.wikipedia.org/wiki/Fusion_power

I know it was for a short period, but 0.5 seconds is enough to prove the concept, and this was the objective then. They did another experiment at a quarter of the output for five seconds, and both were limited by the design of the tokamak not targeting long runs (it's a scientific reactor).

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Re:Isaac Asimov's predictions 50 years on by aetherson on Wednesday April 23, 2014 @01:55PM (#7635667)

I know this is now a pretty dead thread, but just FYI: you're again looking at the comparison of power output to "power absorbed by the particles to be fused," not power output to overall system power input.

All the fusion people are so far from being energy positive to overall system power input, and so far from even trying to get to that milestone, that it's a little hard to find articles that talk about the power input to the whole system. But, to use wikipedia, here's a link:

http://en.wikipedia.org/wiki/Joint_European_Torus

Note that they talk about Q. JET claims a Q of approximately 0.7. Q=1 is what you're talking about -- more energy out of the particles than is absorbed by the particles. Q=5 is potentially self-sustaining -- because, in this case, only 20% of the energy out is in a form that can create more fusion reactions. The article suggests Q=10 as the minimum for overall power output. My guess is that Q=10 is wildly optimistic for that.

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