Diamagnetism of potassium vapor weakly ionized by nonresonant laser radiation

An experimental investigation was made of the generation of a diamagnetic moment in potassium vapor weakly ionized by nonresonant laser radiation and subjected to a static external magnetic field. The magnetic moment was manifested by an induced emf in a measuring coil. The emf due to the diamagnetic moment was induced ~150–350 nsec after the laser pulse. A study was made of the dependences of the emf signals on the power and polarization of the exciting radiation, on the external magnetic field, and on the concentration of the atoms. The induced diamagnetic moment is explained by multiphoton ionization of the potassium atoms, by electron diffusion in the external magnetic field, and by the formation of eddy currents.