Light-induced drift of optically active atoms in a buffer gas is a consequence of the unequal diffusive frictions suffered by the excited and the ground-state atoms. This drift can be used to create an “optical piston,” which is best observed when the piston action is confined to a one-dimensional motion. We show that a novel way of realizing this phenomenon is to apply a magnetic field on charged active atoms.

• Received 28 October 1998

DOI:https://doi.org/10.1103/PhysRevLett.83.710