There's already a technology that can do that - magnetohydrodynamic generation [1]. A conductive material moving through a magnetic field develops a voltage acr

There's already a technology that can do that - magnetohydrodynamic generation [1]. A conductive material moving through a magnetic field develops a voltage across it, which can be used to produce power; a hot plasma is a conductive material with lots of energy that can drive movement. The problem is that most of the energy produced in fusion is in the kinetic energy of neutrons. To capture that energy, you need to slow the neutrons down by collisions with some material, turning the kinetic energy into heat in that material, and then harvest the heat. AIUI, neutrons being neutral, you need that material to be dense (lots of nuclei per unit volume) and have a high neutron cross-section. The plasma in a fusion reactor is neither, so you can't collect the neutron energy in the plasma. Rather, you have to let the neutrons hit some dense blanket surrounding the plasma, collect the energy as heat there, and then harvest that. There are fusion reactions which don't produce neutrons [1], and so where the energy goes into the kinetic energy of charged particles, which is readily collected in the plasma, using MHD or direct conversion [3] (is MHD considered a kind of direct conversion?). But they are much harder to do than the reactions which do produce neutrons, and those are already hard enough! [1] https://en.wikipedia.org/wiki/Magnetohydrodynamic_generator https://en.wikipedia.org/wiki/Magnetohydrodynamic_generator [2] https://en.wikipedia.org/wiki/Aneutronic_fusion https://en.wikipedia.org/wiki/Aneutronic_fusion [3] https://en.wikipedia.org/wiki/Direct_energy_conversion https://en.wikipedia.org/wiki/Direct_energy_conversion