A serious question is the size of the fusion generator. They typically have volumetric power density far lower than a fission reactor or an internal combustion engine. I don't think they will fit in a small truck.
Is this true of helion (ie. Does the plasma density more than compensate for duty cycle and small reaction volume)? They publish some of their stats, but I wasn't willing to put in the effort to turn it into an actual power density figure.
I do not have the data to compute their power density. They are still going to have limits on the power/area of radiation hitting the first wall; the impulsive nature of that radiation will make the problem tougher.
