Experimental study of spontaneous electric field generated by a laser plasma

We report investigations of a space-time structure of the electric field of laser plasma from a solid target. An ArF excimer laser with an intensity of I≅108 W/cm2 was used to produce the plasma on various targets placed in air at atmospheric pressure. A strong difference in both the amplitude (by more than 1–2 orders of magnitude) and the structure of the electric field for conductive and dielectric targets has been observed. The field distribution for a conductive target was found to correspond to a dipole configuration of charges in the laser plasma, while for the dielectric target a quadrupole configuration was revealed. Possible explanations and applications of the observed effect are discussed.