By that I mean the complete radiative wattage of any type of energetic radioactivity or electromagnetic wave or even particle if that's what they output.

My purpose is to compare this to the suns energy output into the Earth of 174 petawatts.

How many Tokamak sized reactors would it take to simulate the sun. And after all their should be many smaller reactors in case one breaks.

  • $\begingroup$ Currently no fusion reactor produces more energy than it consumes. Do you mean net output (which will thus be negative) or gross output? $\endgroup$ – Sideshow Bob Mar 4 '14 at 20:52
  • $\begingroup$ I'm referring to the hypothetical output of a working Tokamak. Or if you want a scaled-up, more-efficient Tokamak. Or if you want - when they get fusion reactors working, and then maybe after another 30 years of advancement in fusion reactor technology, about how much energy will they output per second? $\endgroup$ – Shine On You Crazy Diamond Mar 4 '14 at 20:56
  • $\begingroup$ Here's a deeper question for you to ponder: How does the power generation per unit mass compare for a fusion reactor (or fusion bomb) versus the Sun? I think you might be surprised. $\endgroup$ – user10851 Mar 4 '14 at 21:14

The term "Tokamak" refers to a design, not a size. The planed ITER reactor has the goal of 500 megawatts output. So it would take approximately 300,000,000 such reactors to produce the same power as the solar energy reaching the Earth.


  • $\begingroup$ Will the power / size efficiency increase with scaling up? $\endgroup$ – Shine On You Crazy Diamond Mar 4 '14 at 21:13
  • $\begingroup$ I guess we'll need a factory to mass produce some fusion reactor design once they're working and efficient. Massive containment coils may not be required since the reactors would be in space, far-enough away from Earth. And the idea is not to contain the plasma but to shoot it out at the Earth. So you now have the sun simulated and some thrust. $\endgroup$ – Shine On You Crazy Diamond Mar 4 '14 at 21:18

The highest fusion power generated (briefly) by a tokamak was 16MW by the Joint European Torus (ET). ITER (as DavePhD mentions) is hoping for 500 MW of fusion power (briefly) but it will be years before it is operational. BTW 80% of the energy from a deuterium-tritium (D-T) plasma is in 14.1 MeV neutrons.


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