简介:Radiationsimulationutilizingplasmaradiationsources(PRS)generatesalargenumberofundesirabledebris,whichmaydamagetheexpensivediagnosingdetectors.Anultrafastshutter(UFS)drivenbypulsedhighcurrentcanerectaphysicalbarriertotheslowlymovingdebrisafterallowingthepassageofX-rayphotons.TheUFSconsistsofapairofthinmetalfoilstwistingtheparallelaxesinaNyloncassette,compressedwithanoutermagneticfield,generatedfromafastcapacitorbank,dischargingintoasingleturnloop.Atypicalcapacitorbankisof7.5μFchargingvoltagesvaryingfrom30kVto45kV,withcorrespondingcurrentsofapproximately90kAto140kAanddischargingcurrentperiodsofapproximately13.1μs.Ashutterclosingtimeasfastas38microsecondshasbeenobtainedwithanaluminiumfoilthicknessof100micrometersandacross-sectionalareaof15mmby20mm.Thedesign,constructionandtheexpressionsofthevalve-closingtimeoftheUFSarepresentedalongwiththemeasuredresultsofvalve-closingvelocities.
简介:Highspinstatesintheodd-oddnucleus124Cshavebeeninvestigatedthroughthefusion-evaporationreaction116Sn(11B,3n)124Cswithabeamenergyof45MeV.Anewrotationalbandisestablishedandassignedasthehigh-kconfigurationofπg9/2[404]9/2+νh11/2[523]7/2.Somestructureslinkingtothisbandhavealsobeenobserved.Accordingtotheresultsoftheexcitationenergysystematics,thelowestlevelofthisbandisassignedas9,andthe8isomerbandheadhasnotbeenobserved.Anotherisomerwithahalflifeof6.3shasalsobeenobservedwithitsnewdecaypathsestablished.Itsexcitationenergyisraisedby79keV,butitsIπisnotchanged.
简介:Neutralbeaminjectionisoneofthemainplasmaheatingmethodsinnuclearfusiondevices.InordertosupportthescientificstudyoftheExperimentalAdvancedSuperconductingTokamak(EAST),amegawatt-levelhighcurrentionsourceisdesignedandmanufacturedintheASIPP,andtheprogressandpreliminarytestresultswillbepresentedinthispaper.
简介:InsituhighpressureopticalabsorptionmeasurementsofsulfurhavebeencarriedoutbyusingDACdevicewithaTASCOV-550UV-VISspectrophotometeratpressuresupto41.6GPa.Thecurvesofabsorptionedgevspressurewereobtained.inwhichtherearetwoturningpointsatabout5and12GPa,correspondingtotwochangesofcolourintheopticalobservation:oneisfromyellowtoredandtheotherfromredtoblackat5-6\5and10-12GPa,respectively.Theabsorptionedgereachesabove800nmwhenthepressureisincreasedto23GPa.Thesturctureandphasetransitionshavealsobeeninvestigatedbyusinginsituhighpressureenergy-dispersivex-raydiffractionwithsynchrotronradiationatpressuresupto33.7GPa.Nostructurephasetransitionoccursat5-6GPa.butthereisanewhigh-pressurephase,causedprobablybythereorientationororderingofS8.
简介:InTokomak,thesupportoftheELMcoil,whichisclosetotheplasmaandsubjecttohighradiationlevel,hightemperatureandhighmagneticfield,isusedtotransportandbearthethermalloadduetothermalexpansionandthealternatingelectromagneticforcegeneratedbyhighmagneticfieldandACcurrentinthecoil.AccordingtothefeatureofITERELMcoil,themechanicalperformanceofrigidandflexiblesupportsunderdifferenthighnuclearheatlevelsisstudied.Resultsshowthatflexiblesupportshavemoreexcellentperformanceinhighnuclearheatconditionthanrigidsupports.Concerningthermalandelectromagnetic(EM)loads,optimizedresultsfurtherprovethatflexiblesupportshavebettermechanicalperformancethanrigidones.Throughthesestudies,reasonablesupportdesigncanbeprovidedfortheELMcoilsorsimilarcoilsinTokamakbasedonthenuclearheatlevel.
简介:Plasmafillingcandramaticallyimprovetheperformanceofhighpowermicrowavedevices.Thecharacteristicsofhigh-powermicrowavepropagationalongplasmafilledwaveguidesinanaxialmagneticfieldareanalyzedinthispaper,andtheponderomotiveforceeffectofhighpowermicrowaveistakenintoconsideration.Theoreticalanalysisandpreliminarynumericalcalculationsareperformed.Theanalysesshowthattheponderomotiveeffectwouldchangetheplasmadensity,distributionofmicrowavefieldintensity,anddispersionofwavepropagation.Thehigherthemicrowavepower,thestrongertheponderomotiveeffect.Indifferentmagneticfields,theponderomotiveeffectisdifferent.
简介:Ahigh-currentvacuumarc(HCVA)withtheconsiderationofanodevaporismod-eledandsimulated.First,fromtheHCVAcolumnmodel,theheatfluxdensitytotheanodeisobtained,whichisputintotheanodeactivitymodel,andtheparameterdistributions(suchasthevaportemperatureandvelocity)ofanodevaporareobtainedfromthesimulationresultsoftheanodeactivitymodel.Then,byiteratingandcalculatingtheHCVAcolumnmodelandanodeactivitymodel,theinteractionbetweentheHCVAcolumnandtheanodevaporissimulatedandanalyzed.Inthesimulation,thedistributionoftheaxialmagneticfield(AMF)generatedbytheelectrodesystemiscalculatedbysoftwareANSYS.Thesimulationresultsshowthattheinfluenceofanodevaporontheparameterdistributionsinthearccolumnissignificant.Thesimulationresultsarealsocomparedwiththevacuumarcphotograph.
简介:Inordertotransfertheheatfromthearmortothecoolant,tungstenhastobeconnectedwithacopperheatsink.Thejointtechnologyisthemostcriticalissueformanufacturingplasmafacingcomponents.Consequently,thereliabilityofthejointsshouldbeverifiedbyagreatnumberofhigh-heat-flux(HHF)teststosimulatetherealloadconditions.W/CubrazedjointtechnologywithsliverfreefillermetalCuMnNihasbeendevelopedatSouthwesternInstituteofPhysics(SWIP).Screeningandthermalfatiguetestsofonesmall-scaleflattileW/CuCrZrmockupwereperformedona60kWelectron-beamMaterialtestingscenario(EMS-60)constructedrecentlyatSWIP.Themodulesuccessfullysurvivedscreeningtestwiththeabsorbedpowerdensity(Pabs)of2MW/m2to10MW/m2andthefollowing1000cyclesatPabsof7.2MW/m2withouthotspotsandoverheatingzonesduringthewholetestcampaign.MetallurgyandSEMobservationsdidnotfindanycracksatbothsidesandtheinterface,indicatingagoodbondingofWandCuCrZralloy.Inaddition,finiteelementsimulationsbyANSYS12.0underexperimentalloadconditionswereperformedandcomparedwithexperimentalresults.
简介:Inlowerhybridcurrentdrive(LHCD)experimentsinHT-7,LHwavecoupledtotheplasmafrom12klystronsislaunchedbyaphasedmulti-junctiongrill.Highpowermicrowavereflectionorarc,whichthreatenstheklystrons,thewave-guideceramicwindowsandthevacuumofthetokamak,occursometimesduringtheexperiments.Forthesakeofsafety,ahighpowermicrowavetestsystemtoperformsimulationswasdeveloped.Inthetestexperiments,theklystronandwindowcanbewellprotectedwithanoptimizedmicrowavemonitorandaPINswitch.ThelayoutofthetestsystemandthesimulatedexperimentsforHT-7aredescribedinthispaper.
简介:Hybridcircuitbreaker(HCB)technologybasedonavacuuminterrupterandaSF6interrupterinserieshasbecomeanewresearchdirectionbecauseofthelow-carbonrequirementsforhighvoltageswitches.Thevacuuminterrupterhasanexcellentabilitytodealwiththesteeprisingpartofthetransientrecoveryvoltage(TRV),whiletheSF6interruptercanwithstandthepeakpartofthevoltageeasily.AnHCBcantakeadvantageoftheinterruptersinthecurrentinterruptionprocess.Inthisstudy,anHCBmodelbasedonthevacuumiondiffusionequations,iondensityequation,andmodifiedCassie-Mayrarcequationisexplored.Asimulationplatformisconstructedbyusingasetofsoftwarecalledthealternativetransientprogram(ATP).AnHCBprototypeisalsodesigned,andtheshortcircuitcurrentisinterruptedbytheHCBunderdifferentactionsequencesofcontacts.ThevoltagedistributionoftheHCBisanalyzedthroughsimulationsandtests.TheresultsdemonstratethatifthevacuuminterrupterwithstandstheinitialTRVandinterruptsthepost-arccurrentfirst,thentherecoveryspeedofthedielectricstrengthoftheSF6interrupterwillbefast.Thevoltagedistributionbetweentwointerruptersisdeterminedbytheirpost-arcresistance,whichhappensaftercurrent-zero,andsubsequently,itisdeterminedbythecapacitiveimpedanceafterthepost-arccurrentdecaystozero.
简介:TheHTScurrentleadsofsuperconductingmagnetsforlargescalefusiondevicesandhighenergyparticlecolliderscanreducethepowerconsumptionforcoolingby2/3comparedwithconventionalleads.Theresistivesectionsofhigh-ratedcurrentleadsareusuallymadeofaheatexchangercooledbygasflow.Thesupplyofthecoolingmassflowincursmorethan90%ofthecoolingcostfortheHTSleads.Themassflowraterequirementdependsnotonlyonthelengthandmaterialoftheresistiveheatexchanger,butalsoontheheattransfercoefficientandHEXsurface,thejointresistanceatthecoldendanditscoolingapproach.Thedesignandoperationofasheet-stackHEXwithalargerspecificsurfaceandamuchsmallerhydraulicdiameterarepresentedinthepaper.ThetestresultsofanHTSleadoptimizedfor8kAshowthata98.4%efficiencycanbeachieved.
简介:StationarylongpulseplasmaofhighelectrontemperaturewasproducedonEASTforthefirsttimethroughanintegratedcontrolofplasmashape,divertorheatflux,particleexhaust,wallconditioning,impuritymanagement,andthecouplingofmultipleheatingandcurrentdrivepower.Adischargewithalowersinglenulldivertorconfigurationwasmaintainedfor103sataplasmacurrentof0.4MA,q95≈7.0,apeakelectrontemperatureof>4.5keV,andacentraldensityne(0)2.5×1019m-3.Theplasmacurrentwasnearlynon-inductive(Vloop<0.05V,poloidalbeta0.9)drivenbyacombinationof0.6MWlowerhybridwaveat2.45GHz,1.4MWlowerhybridwaveat4.6GHz,0.5MWelectroncyclotronheatingat140GHz,and0.4MWmodulatedneutraldeuteriumbeaminjectedat60kV.Thisprogressdemonstratedstrongsynergyofelectroncyclotronandlowerhybridelectronheating,currentdrive,andenergyconfinementofstationaryplasmaonEAST.Itfurtherintroducedanexampleofintegrated'hybrid'operatingscenarioofinteresttoITERandCFETR.
简介:APlasmaSurfaceInteraction(PSI)experimentonChinaLowActivationMarten-sitic(CLAM)steelwasdonetocheckifCLAMsteelcouldbeusedasaPlasmaFacingMaterial(PFM).Aspecimenwithadiameterof45mmwasexposedto897shotsofdeuteriumplasmaswithatotaldurationof712secataminorradiusof30cminHT-7tokamak.Duringtheexpo-sureexperiment,noobservableinfluencewasfoundonplasmaperformance.Afterexposure,thesurfaceofthespecimenseemedassmoothasbeforebutwithsomecolourchangeatthemarginofthespecimen.Eventhoughsomemicro-damage,suchasdenseblisters,melting,splashing,depositions,anddust,wasfoundonlocalsurfaceswithScanningElectronMicroscopic(SEM)observation.Thereflectivityofthespecimendecreasedonlyslightly.AlloftheseshowsCLAMsteelhasgoodstabilityandirradiationresistance.Withfurtheroptimization,itcouldpossiblybeusedasthefirstmirrormaterialforplasmadiagnosticsintokamaks.
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简介:Atwo-dimensionalhybridcodeisdevelopedtomodelthetransportofahigh-currentelectronbeaminadenseplasmatarget.Thebeamelectronsaretreatedasparticlesanddescribedbyparticle-in-cellsimulationincludingcollisionswiththetargetplasmaparticles.Thebackgroundtargetplasmaisassumedtobeastationaryfluidwithtemperaturevariations.Thereturncurrentandtheself-generatedelectricandmagneticfieldsareobtainedbycombiningAmpere’slawwithoutthedisplacementcurrent,theresistiveOhm’slawandFaraday’slaw.Theequationsaresolvedintwo-dimensionalcylindricalgeometrywithrotationalsymmetryonaregulargrid,withcenteredspatialdifferencingandfirst-orderimplicittimedifferencing.Thealgorithmsimplementedinthecodearedescribed,andanumericalexperimentisperformedforanelectronbeamwithMaxwelliandistributionejectedintoauniformdeuterium-tritiumplasmatarget.