Intheplasmasheathanarrowplasmachannelgeneratedbyultraintenselaserpulsesissimplifiedasaspecialcylindricalandhollowplasmawaveguidewiththeinfinitethicknessoftheplasmacladding.Theelectromagneticwave(EM)propagationpropertiesoftheplasmachannelnearthecutoffandfarfromthecutoffareconsidered.TheoreticalanalysisshowsthatTE0mandTM0mandhybridmodesemergeintheplasmachannel,whichisinfluencedbythenormalizedfrequencyparameterBandnumericalapertureNA.Thecutoffsofthevariousmodesareapproximated.Single-modeoperationispossiblewithoutahigh-frequencylimitationinthechannel.