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National Ignition Facility Takes First Steps Towards Fusion Energy
sciencehabit writes "As it approaches its fifth birthday, the National Ignition Facility (NIF), a troubled laser fusion facility in California, has finally produced some results that fusion scientists can get enthusiastic about. In a series of experiments late last year (abstract 1, abstract 2), NIF researchers managed to produce energy yields 10 times greater than produced before and to demonstrate the phenomenon of self-heating that will be crucial if fusion is to reach its ultimate goal of 'ignition'—a self-sustaining burning reaction that produces more energy than it consumes."
The best performance of a tokamak I know of was the JET run back in the 90s where they got about 22MJ out of plasma in about 1.5 seconds, a rate of 15MW for that time. It was nowhere near "ignition", it took significantly more energy to create that plasma than it emitted while it lasted.
The NIF people talk about "ignition" because that's what they do, it's in their name after all. Magnetic fusion people talk about Q factor. Q=1 is breakeven where the same amount of fusion energy is produced as is pumped in to make and heat the plasma. I think the best Q figure JET has ever achieved is about 0.6 and only for a very brief time.
The ITER tokamak under construction on France is expected to return values of Q > 10 eventually, with 50MW input producing more than 500MW of thermal energy in a fusion plasma that can be sustained for hundreds of seconds and hopefully it won't have to be rebuilt after every run.