Eddy Current III

In an electromagnetic launcher, a coil is wrapped around an iron core and an alternating current is applied to this coil. This will produce an alternating magnetic field in the iron core. If a conducting ring is placed on the iron core, an Eddy current will be induced around the ring. This Eddy current is in the same direction as the current in the coil and the magnetic force acting on the Eddy current will launch the ring upward. If a slot is cut through the ring so it cannot conduct the current, then there will be no magnetic force and the ring will not be launched. Not so obvious question: Why the Eddy current is always in the same direction as the alternating current in the coil?