Self-focusing of a laser beam in an inhomogeneous plasma

An analysis is presented of self-focusing of a Gaussian laser beam in an axially inhomogeneous plasma. The nonlinearity in the dielectric constant arises on account of the carrier-redistribution caused by ponderomotive force or nonuniform heating of electrons with or without thermal conduction. It is seen that the laser beamwidth tends to attain a constant value depending upon the plasma inhomogeneity and initial laser intensity. Anomalous penetration of a laser beam has also been investigated in overdense plasmas with different types of inhomogeneities. (author)