4 ms·

Magnetic breaking is still quite feasible. There are some interesting proposals to build "Q" drives, which would use plasma magnets to generate energy from the

• pfdietz 5y ago
  This approach could also work with interstellar plasmas, using the motion of the vehicle vs. the plasma to generate power, which then is used to generate thrust by expelling reaction mass. This is not perpetual motion: it is concentrating the initial kinetic energy of the vehicle (in the rest frame of the interstellar medium) in less and less mass as reaction mass is expelled. This might be implemented by using diffuse structures to induce a plasma wave in the ISM, and then accelerating particles in that wave's electric field. No large compression of the plasma (as a putative fusion-based drive would need) is required.