The electromagnetic pump is an application of Fleming's Left Hand Rule. When a current passes through a magnetic field, the conducting medium – be it a liquid or solid conductor – experiences a force at right angles to both the direction of the current and the magnetic field. If the conducting medium is a liquid, the liquid will flow.
There electromagnetic pump is useful to pump liquids in places that cannot be accessed. Two very good examples are their use in nuclear power stations, where they can be used to pump cooling fluid – liquid sodium - around the reactor core, and in the human body, to assist the heart in pumping if it is damaged.