Hall Thrusters
Ionize xenon or krypton and accelerate ions with electric and magnetic fields.
Electric rockets
High efficiency, low thrust, long duration.
Electric propulsion is not a launch replacement from Earth, but it is powerful for in-space station-keeping, orbit raising, and deep-space missions.
Gridded Ion
Very high specific impulse with low thrust, suited to long-duration science and commercial spacecraft.
Nuclear Electric
A reactor can provide electric power for efficient low-thrust propulsion over long periods.
Reality Check
Electric propulsion can reach high total velocity over time, but thrust is too low for launch from Earth. Chemical rockets remain necessary for liftoff.