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Helion is a non-ignition fusion reactor. They aim to avoid the need for ignition by having efficient energy recapture. The website goes into more detail, and th
by Veedrac 5y ago
Helion is a non-ignition fusion reactor. They aim to avoid the need for ignition by having efficient energy recapture. The website goes into more detail, and the prototypes have demoed this capability.
- jjk166 5y agoThe lawson criterion is the point at which the plasma is heated by fusion faster than it is cooled by losses. It is a lower threshold than ignition. Even without ignition, you still need to achieve it to produce net power. Ironically, their efficient method of energy capture actually makes their job harder than for a thermal system where heat losses due to bremsstrahlung and neutron heating are partially recovered; indeed this is the output for a conventional fusion reactor. For helion, only the energy of the plasma is harvested and thus they must exceed breakeven by enough to not just maintain but to heat the plasma by some economically useful amount.
- Veedrac 5y agoI'm confused. I thought the Lawson criterion was the threshold for ignition, and Google seems to be backing me up. Am I missing a subtlety here?
- jjk166 5y agoGoogle is oversimplifying. The lawson criterion is defined to be the point where heat production by the plasma equals heat loss. For tokamaks (and other magnetic confinement fusion reactors where the confinement time is very long) reaching the lawson criterion is basically all you need to do to achieve ignition - once the plasma is being heated by fusion reactions faster than it is losing heat, it will very rapidly reach the point where it ignites with no further external input. For short duration fusion (ICF, Magnetized target, Helion, etc) you can exceed the lawson criterion and thus produce gain, but the plasma may still not be long enough lived for the fusion to actually induce more fusion (which is the actual ignition point).
- Veedrac 5y agoThanks, I get you now.