I was reading about possible future propulsion systems and they all pretty much work by accelerating fuel back to produce forward thrust, accept for magnetic propulsion. Initially when you first turn on the current to an electro magnet there is a rapid oscillation that occurs until the magnet reaches a stable charge. I understand that. How its actually said to work is if you can turn the magnet on and off for half the oscillation period it will only oscillate in one direction producing thrust. My question is why does the magnet always start its oscillation in the same direction? The concept sounds way too simple not to have been perfected yet, so why hasn't it yet?