简介:Thezonalfieldseffectonthebeta-inducedAlfveneigenmode(BAE)destabilizedbytheenergeticparticlesintoroidalplasmasisstudiedthroughthegyrokineticparticlesimulations.ItisfoundthatthelocalizedzonalfieldswithanegativevaluearoundthemoderationalsurfacearegeneratedbythenonlinearBAE.Intheweaklydrivencase,thezonalfieldswithastronggeodesicacousticmode(GAM)componenthaveweakeffectsonthenonlinearBAEevolution.Inthestronglydrivencase,thezonalfieldsaredominatedbyamoresignificantzerofrequencycomponentandhavestrongereffectsonthenonlinearBAEevolution.
简介:InHL-2Atokamaks,thebehaviorofheatfluxdepositedonthedivertortargetshasbeenstudiedduringdeuteriumgasfuelling.Theheatfluxisreducedsignificantlyaftersupersonicmolecularbeaminjection(SMBI)fuellingduringOhmicandelectroncyclotronresonanceheating(ECRH)divertordischarges.TheSMBIfuellingcausesanincreaseintheplasmadensityandthischangeresultsintheexperiencedchangeoftheedgeproperties.MostofthisreductionindivertortargetheatfluxoccurstogetherwithahighplasmaradiationregionlocatedatneartheX-point.Thelargestreductioninheatfluxprofilesisobservedattheoutboarddivertorseparatrixstrikepoint,whiletheheatfluxfarfromthestrikepointremainsalmostunchanged.Inparticular,withSMBImulti-pulsesgasfuelling,apartiallydetacheddivertorregimeisobservedwithahighlyradiatingregionattheX-point.Withtheonsetofthepartiallydetacheddivertorregime,asuddendropinbothheatfluxandpowerflowonthedivertortargetisobserved.Thereductioninpowerloadonthedivertortargetsisroughlyequaltotheincreaseinplasmaradiationloss.
简介:Theq-profilecontrolproblemintheramp-upphaseofplasmadischargesisconsid-eredinthiswork.Themagneticdiffusionpartialdifferentialequation(PDE)modelsthedynamicsofthepoloidalmagneticfluxprofile,whichisusedinthisworktoformulateaPDE-constrainedop-timizationproblemunderaquasi-staticassumption.Theminimumsurfacetheoryandconstrainednumericoptimizationarethenappliedtoachievesuboptimalsolutions.Sincethetransientdy-namicsispre-givenbytheminimumsurfacetheory,thenthismethodcandramaticallyacceleratethesolutionprocess.Inordertoberobustunderexternaluncertaintiesinrealimplementations,PID(proportional-integral-derivative)controllersareusedtoforcetheactuatorstofollowthecomputationalinputtrajectories.Ithasthepotentialtoimplementinreal-timeforlongtimedischargesbycombiningthismethodwiththemagneticequilibriumupdate.