To me it seems the paper's conclusion is more that to a KII civilization, a Bussard ramjet is already a toy. If you have the energy output of a sun at your dis

To me it seems the paper's conclusion is more that to a KII civilization, a Bussard ramjet is already a toy. If you have the energy output of a sun at your disposal, laser propulsion seems like a vastly more attractive solution, except for the problem posed by deceleration which is not insurmountable. Indeed, the ~Mm scale solenoid discussed in the paper seems something that should be easily within the reach of a KI scale civilization if they really want to build one. Or several.