You raise some good points. > Inertial confinement fusion like the NIF is not intended to run continuously, so the 2ns duration is irrelevant. Indeed. I do th

You raise some good points. > Inertial confinement fusion like the NIF is not intended to run continuously, so the 2ns duration is irrelevant. Indeed. I do think ICF has a future. The issue I described applies to machines that attempt to achieve sustained fusion. Pulsed fusion is ok. > The heat loss is practically limited by the mass of hydrogen fusing in the machine. Yes, but it goes the other way too. If the heat loss is to high you can't sustain fusion because you can't stay at the required temperature for long enough.