Abstract: Theadaptabilityofcuspedfieldthrusterchangeswithdifferentoperatingconditions,especiallywithdifferentefficiencies,whichchangesalotatdifferentgasflowrates.Toovercomethisproblem,adivergingvariablecrosssectionchannelwasproposedtoimprovetheperformanceofcuspedfieldthrustersatlowandmiddlegasflowrate.Meanwhile,twoconstantsectionchannelswithabigdiameteranda  smalldiameterrespectivelywereintroducedtobecomparedwiththedivergingchannel.Althoughthedivergingchannelmaycausealittledeclineintheatomdensitycomparedtothesmall  constantsectionchannel,thedivergingchannelimprovestheefficiencyatbothlowandmiddlegasflowratesonthepremiseofprovidingaconsiderablethrust,becauseitdecreasestheenergylossofionsatexitandpromotesionizationbyimprovingthemagneticmirrorratio.Incomparison,boththebigconstantsectionchannelandthesmallconstantsectionchannelhavelowperformancesduetoalowerdensityofgasandabiggerwallloss.Therefore,adivergingchannelisbeneficialtoimprovingtheperformanceofacuspedfieldthrusteratlowandmiddlegasflowrate.

Key words: cuspedfieldthruster, divergingchannel, lowandmiddlegasflowrate, directsimulationMonteCarlo