简介：Numericalsolutionstofloatingplasmapotentialsforwallsemittingsecondaryelectronsareobtainedforvarioussurfacematerials.Thecalculationsaremadewithplasmamomentequationsandthesecondaryelectronemissioncoefcients,whichweredeterminedfromrecentlaboratoryexperiments.Theresultsestimatethewallpotentialsuptothephysicalconditionsthatallowstableplasmasheathsunderthespace-charge-limitedcondition.Thematerialsoftenusedinthelaboratory,suchasaluminum,silicon,boron,molybdenum,silicondioxide,andalumina,areconsidered.Theminimumwallpotentialbeforetheonsetofspace-charge-limitedemissionisdeterminedbytheelectrontemperaturesatwhichtheefectivesecondaryelectronemissioncoefcientintegratedoverthevelocitydistributionsisabout0.62.Thecorrespondingpotentialisgivenby-eφ0~1.87kBT.Theconditionforspace-charge-limitedemissionisnewlyfoundbynumericallysearchingforallthestablesheaths.Thenewconditionis-eφ0~0.95kBT,andthispredictsawallpotentialthatislessnegativethanthepreviouslyfoundone.Calculationofthepowerdissipatedtothewallforhydrogenplasmasshowsthatthereisalargediferenceintermsofpowerdissipationamongtheconsideredmaterialsinthetemperaturerange20~50eV.