简介:ThepropagationofquadrupleGaussianlaserbeaminaplasmacharacterizedbyaxialinhomogeneityandnonlinearityduetoponderomotiveforceintheparaxialrayapproximationisinvestigated.Anappropriateexpressionforthenonlineardielectricconstanthasbeendevelopedinthepresenceofexternalmagneticfield,withlinearabsorptionandduetosaturationeffectsforarbitrarylargeintensity.Theeffectsofdifferenttypesofplasmaaxialinhomogeneitiesonself-focusingoflaserbeamhavebeenstudiedwiththetypicallaserandplasmaparameters.Self-focusingofquadrupleGaussianlaserbeaminthepresenceofexternallyappliedmagneticfieldandsaturatingparameterisfoundsignificantlyimprovedinthecaseofextraordinarymode.Ourresultsrevealthatinitiallyconvergingbeamshowsoscillatoryconvergencewhereasinitiallydivergingbeamshowsoscillatorydivergence.Thebeamismorefocussedatlowerintensityinbothcasesviz.extraordinaryandordinarymode.