MAGNETOHYDRODYNAMIC DRIVE
Purpose and Application: A pair of superconducting coils produce a strong magnetic field in a gap where seawater can flow perpendicular to the field. In addition, an electric field is generated perpendicular to the seawater flow using a pair of charged plates. The magnetic, electric field, and electrically conductive seawater interact, causing a force to be exerted on the seawater causing it to move through the gap. The reaction force from the moving seawater produces thrust. Being considered by the Navy for quiet submarine electric drive.
Example: A concept has been developed by Lockheed Martin for the Navy using the water flowing in an annulus configuration around the hull of a submarine.