简介:Radiointerference(RI),asanaftereffectofcoronadischarge,isanimportantresearchtopicinthefieldofelectromagneticcompatibility,whereexcitationfunctionisappliedbroadlytothepredictionofRIlevel.ThispaperpresentsthetheoryofexcitationfunctionmethodusedintheRIlevelprediction.Then,somepracticalproblemsrelatedtothismethodarediscussed.Thepropagationprocedureofcoronacurrentissolvedbythephase-modaltransformation,andtheimpedancematrixofmultitransmissionlinesiscalculatedbyadoublelogarithmicapproximatemodelofCarson'sGround-Returnimpedance.Atthesametime,inordertocalculatetheRIlevelwhentotallinecoronaisassumed,ananalyticalformulaisdeducedforintegraloperation.Basedontheabovesolutions,analgorithmispresentedandappliedtothepredictionofRIlevelofapracticaloverheadtransmissionline.Comparisonofpredictionandmeasurementresultsindicatesthatthealgorithmproposedinthispaperiseffectiveandfeasible.
简介:Ionopticsisacriticalcomponentofionthrusters.Atwo-dimensionalaxisymmetricmodelisdevelopedtostudythecharacteristicsofthree-gridelectroncyclotronresonanceionthrusteroptics.Thecodeisbasedonaparticle-in-cellcombinedwiththeMonteCarlocollisionmethodtosimulateiondynamicsandcharge-exchangeprocessesinthegridregion.Thesimulationresultsshowthatthemodecangiveareasonableestimateofthephysicscharacteristicsoftheionoptics.Thedesignoftheionopticssatisfiestherequirementofpreventingelectronbackstreaming.Charge-exchangeionscancausedamagetothegrids,especiallytotheacceleratorgrid.'Barrel'erosioncanincreasetheacceleratorgridapertureradiusatarateof1.91×10~(-11)m/s,whilethedeceleratorgridplaysanimportantroleinreducing'pits-and-grooves'erosion.
简介:Thispaperproposesanewmethodtopredictthecoronaonsetvoltageforarodplaneairgap,basedonthesupportvectormachine(SVM).BecausetheSVMisnotlimitedbythesize,dimensionandnonlinearityofthesamples,thismethodcanrealizeaccuratepredictionwithfewtrainingdata.Onlyelectricfieldfeaturesarechosenastheinput;nogeometricparameterisincluded.Therefore,theexperimentdataofonekindofelectrodecanbeusedtopredictthecoronaonsetvoltagesofotherelectrodeswithdifferentsizes.Withtheexperimentaldataobtainedbyozonedetectiontechnology,andexperimentaldataprovidedbythereference,theefficiencyoftheproposedmethodisvalidated.Accuratepredictedresultswithanaveragerelativelessthan3%areobtainedwithonly6experimentaldata.