Yeah, but raw fusion energy to heat is not nearly as trivial as it sounds. And given how tricky it is to sustain a fusion reaction it seems like it will be even harder to do it when you're dealing with moving heat from the source of the fusion reaction to wherever your steam generator is.

From my guess, the plasma is already quite hot, so you could do whatever you do to cool it normally, just more so because it’s self-sustaining.

I believe there are two main ways of cooling: convection and radiation. Convection requires a gas or liquid carrier to be in contact with the hot substance; it seems like it would be very difficult to get water (steam) into direct contact with the plasma to transfer the heat, and then to carry the heat away without the radioactive plasma along with it.

Radiation is a function of temperature (to the 4th power) and surface area. It seems even harder to channel the heat from the plasma to the engine this way.

So how would you do either of these 'more so'?