A variable reluctance solenoid (101) includes an armature (330) and a yoke located axially beyond one end of the armature (330). Magnetic attraction across an axial gap (34) between the armature (330) and yoke causes the armature (330) to move axially and close the gap (340). The armature (330) includes ferromagnetic laminations lying in a plane perpendicular to the axial direction. These laminations may include slots, proportioned and directed to combat eddy currents and reduce moving mass while avoiding creation of flux bottlenecks. The solenoid (101) may have two yokes on opposite sides of the armature (330), providing reciprocating armature motion.
