Comment by api

AFAIK superconductors are a major limiting tech. But we are slowly getting better ones, both by discovering more and by learning to mass produce superconducting wire.

With superconductors you can make magnetic bottles.

There’s also some interesting inertial confinement work happening. There the limiter is both confinement and the efficiency of the driver. Look up MagLIF for a hybrid magnetic inertial approach under study.