In one example, an x-ray tube comprises an evacuated enclosure and a cathode disposed within the evacuated enclosure. An anode is also disposed within the evacuated enclosure opposite the cathode so as to receive electrons emitted by the cathode. A rotor sleeve is coupled to the anode, the rotor sleeve being responsive to applied electromagnetic fields such that a rotational motion is imparted to the anode. A magnetic assist bearing assembly rotatably supports the anode.