Controlling the Self-Focusing of Quadruple Gaussian Beam in Plasma

The aim of this paper was to investigate the self-focusing dependence of the quadruple Gaussian beam on effective parameters. Based on the introduced model of focusing parameter (FP), the nonlinear self-focusing dependence on the beam separation and the initial intensity of beam are found. The results indicate that the focusing dependences on the intensity and separations are coupled and the form of focusing dependence on separations nonlinearly differs by changing the intensity of the beam. The nonlinearity is clarified by finding the nonlinear impact of the initial intensity of beam on self-focusing. Based on the proposed model, the impacts of the plasma frequency, beam separation, and initial intensity on the spot size reduction are also compared. All the results are validated by solving the differential equation of beamwidth in plasma, and good conformity is obtained. The presented model is applicable for controlling the rate of self-focusing of quadruple beam by means of desired selection of lateral beam separation, the beam intensity, and the plasma frequency.