You don't have to chuck in rods, that's just the intuitive explanation for why you oughta be able to take energy back out. Realistically (for a certain value of

You don't have to chuck in rods, that's just the intuitive explanation for why you oughta be able to take energy back out. Realistically (for a certain value of realism) you'd use the magnetic field generated by charged particles accelerated in such a fashion, or something like that