Second harmonic generation of Cosh-Gaussian beam in unmagnetized plasmas: Effect of relativistic-ponderomotive force

Second harmonic generation (SHG) of Cosh-Gaussian beam in unmagnetized plasma is investigated in present communication. The relativistic-ponderomotive force (RP force) is jointly taken in present investigation. The combined action of RP force produces electron redistribution thereby producing density fluctuations in plasma in transverse direction. Electron plasma wave (EPW) is generated at pump beam's frequency on account of these density fluctuations. The pump beam couples with EPW resulting in generation of 2nd harmonics. The nonlinear differential equation associated with pump beam and second harmonic yields (SHY) are obtained by employing WKB and paraxial theory approximations. The overall impact of established laser plasma parameters and RP force on pump beam's focusing ability and SHY is also explored.