Theplasma-neutralgasstructuregeneratedinamagnesiumcathodicarcoperatedwithoxygengasataconstantcurrentof50Ahasbeeninvestigatedbyemployingasimplifiedone-dimensionalfluidmodel.Themodelincludeselasticcollisionsandcharge-exchangereactionsbetweenmetallicparticlesandgasmolecules,andalsogenerationandrecombinationofgaseousionsbyelectronimpact.Thedistributionprofilesofdensityandvelocityofspeciesalongtheaxialdirectionwereobtainedatdiferentbackgroundgaspressures(intherangeof0.7~3.0Pa)bythismodel.Acomparisonwiththeexperimentswasmade.Atlowergaspressures,thedepositingparticlesweremainlythemetallicionswithalargerkineticenergy.Asthegaspressureincreased,themagnesiumatomswithsmallerkineticenergyactedasthedominantdepositingspecies.Determinedbytheminimizationofthesystem’stotalenergy,MgO(100)or/andMgO(110)orientationappearedeasilyintheMgOfilmsatlowergaspressures,andathighergaspressures,thefilmpreferredorientationwasMgO(111).
