简介:Characteristicsofiontemperaturemeasuredwithcharge-exchangerecombinationspectroscopy(CXRS)werestudiedinOhmic,lower-hybrid-wave(LHW)drivenandion-cyclotron-resonance-frequency(ICRF)heatedplasmasinHT-7.TheresultsindicatethatthecentraliontemperatureTi0followstheone-thirdpowerlawintheproductofcentralline-averageddensityneandplasmacurrentIpinOhmicdischargesandisthereforeconsistentwiththeArtsimovichscalinglawTi0=K·(Ip·Bt·ne·R2)1/3.ItisshownthatthereisanappreciableincreaseofiontemperatureduringtheoperationwithbothLHWandICRFandthattheincrementofiontemperatureinthoseshotsismainlyduetotheenergytransferviacollisionsbetweenionsandelectronsratherthatbydirectheatingoftheions.
简介:SawtoothcontrolexperimentswereperformedonHT-7withalimiterconfigurationandontheExperimentalAdvancedSuperconductingTokamak(EAST)withadoublenullcon-figuration.Thesawtoothperiodcanbemodifiedbylowerhybridwave(LHW)andioncyclotronresonancefrequency(ICRF).Differentsawtoothbehaviorwasobservedwiththesameplasmadensity,LHWpowerbutdifferentplasmacurrentsonHT-7.TherewasadwelltimebetweenLHWaddedandthesawtoothstabilizationonHT-7whilethesawtoothstabilizationimmediatelyhappenedwhenLHWpowerwasinjectedonEAST.Thepossiblemechanismofthesawtoothcontrolisdiscussedinthispaper.Alltheexperimentalresultshaveprovedthatpowerdepositionoftheradiofrequency(RF)shouldbethekeyfactorforsawtoothcontrol.
简介:Experimentsonlowerhybridwave(LHW)couplingwereinvestigatedintheHT-7tokamak.GoodcouplingofLHWplasmahasbeendemonstratedatdifferentconditionsintheHT-7tokamak.RelevantresultshaveprovedthatLHW-plasmacouplingisaffectedbythephasedifferencebetweenadjacentwaveguides.Furthermore,theedgedensityaroundthegrillandrelevantcouplingcanbeadjustedbychangingtheplasmalineaveragedensityorthegapvaluebetweentheLHgrillandthelastclosedfluxsurfaces(LCFS).ItisfoundthatthecouplingofLHWsbecomespoorwhentheedgedensityaroundtheLHgrillislargeenoughintheHT-7tokamak,andthatcouplingremainsgoodwithaproperedgedensity.WithincreasingLHWpower,itisalsofoundthatthereflectioncoefficients(RCs)increaseduetonon-lineareffectsunderconditionsoflowedgerecycling,butcandecreaseunderhighedgerecycling.Theedgedensitydependsmainlyonthecompetitionbetweentheponderomotiveforce(PMF)andtheedgerecyclingintensityintheHT-7tokamak.
简介:SawtoothactivityonHT-7tokamakhasbeeninvestigatedexperimentallymainlybyusingsoftx-raydiodearrayandmagneticprobes.Theirbehaviorsandoccurrencesarecorrelatedcloselytothedischargeconditions:theelectrondensityNe,theelectrontemperatureTe,thesafetyfactorqaonplasmaboundaryandwallconditionetc.Whencentralline-averagedelectrondensityNe(0)isover2.0×1013cm-3,majorsawtoothactivityemergeswithaperiodofupto6.5msandafluctuationamplitudeofupto2~30%ofSXRradiationsignal.Insomecasessuchasthesafetyfactorbetween4.2~4.7andZeff=3.0~6.0,amonstersawtoothactivityoftenemergeswithoutapparentdeteriorationofplasmaconfinementandwithoutmajordisruption.Duringtheseevents,abundantMHDphenomenaareobservedincludingpartialsawtoothoscillations.Inthispaper,theobservedsawtoothbehaviorsandtheirdependenceontheandtheirdependencedensityNeandwallconditioninohmicallyheatedplasmaareintroduced,theresultsarediscussedandpresented.
简介:TheICRF(IonCyclotronRangeFrequency)cleaningtechniquehasbeenusedasaroutinewallcleaningmethodintheHT-7superconductingtokamak.Inawiderangeoftoroidalfield,thcremovalrateofresidualgasbyICRFcleaningwasabouttwentytimeshigherthanthatofglowdischargecleaning(GDC).AtdifferentgaspressureandRFpowerlevels,theICRFcleaningisstudiedcarcfully.Agoodimpurityclcaningeffectandaveryhighhydrogenremovalratewereobtained.Theremovalrateofhydrogenby5kWICRFcleaningachievedwas1.6×10-5Torr.1/s.AndtherelationshipsamongpressureP,outgassingrateQ,atomiclayersLabsorbedonsurfaceandthecleaningmodewerediscussedbriefly.
简介:Thispaperreportsforthefirsttimeanexperimentalstudyonthepowerdepositionprofileoftheioncyclotronrangefrequencies(ICRF)powerdepositingonelectronsinHT-7.ThefastFouriertransform(FFT)analysisandthebreakinslope(BIS)methodareutilizedtoobtaintheinformationofthepowerdeposition.Theresultsindicatethattheelectronswereheateddirectly,andtheelectronsabsorbedaround20%oftheinputpowerofthedischargeofinterest.
简介:Togetanoptimizedpulsedelectricalplasmadischargereactorandtoincreasetheenergyutilizationefficiencyintheremovalofpollutants,twohybridplasmadischargereactorsweredesignedandoptimized.Thereactorswerecomparedviathedischargecharacteristics,energytransferefficiency,theyieldsoftheactivespeciesandtheenergyutilizationindyewastewaterdegradation.TheresultsshowedthatunderthesameACinputpower,thecharacteristicsofthedischargewaveformofthepoint-to-platereactorwerebetter.UnderthesameACinputpower,thetworeactorsbothhadalmostthesamepeakvoltageof22kV.Thepeakcurrentofthepoint-to-platereactorwas146A,whilethatofthewire-to-cylinderreactorwasonly48.8A.Thepeakpowersofthepoint-to-platereactorandthewire-to-cylinderreactorwere1.38MWand1.01MW,respectively.Theenergyperpulseofthepoint-to-platereactorwas0.2221J,whichwasabout29.4%higherthanthatofthewire-to-cylinderreactor(0.1716J).Toremove50%AcidOrange7(A07),theenergyutilizationsofthepoint-to-platereactorandthewireto-cylinderreactorwere1.02×10-9mol/Land0.61×10-9mol/L,respectively.Inthepoint-toplatereactor,theconcentrationofhydrogenperoxideinpurewaterwas3.6mmol/Lafter40minofdischarge,whichwashigherthanthatofthewire-to-cylinderreactor(2.5mmol/L).Theconcentrationofliquidphaseozoneinthepoint-to-platereactor(5.7×10-2mmol/L)wasabout26.7%higherthanthatinthewire-to-cylinderreactor(4.5×10-2mmol/L).Theanalysisresultsofthevarianceshowedthatthetypeofreactorandreactiontimehadsignificantimpactsontheyieldsofthehydrogenperoxideandozone.ThemaindegradationintermediatesofA07identifiedbygaschromatographyandmassspectrometry(GCMS)wereaceticacid,maleicanhydride,pbenzoquinone,phenol,benzoicacid,phthalicanhydride,coumarinand2-naphthol.Proposeddegradationpathwayswereelucidatedinlightoftheanalyzeddegradationproducts.
简介:DedicatedexperimentsintheHT-7tokamakwereperformedtoinvestigatethein-fluenceoferosionanddepositiononthemirrorsamples.Thefirstmirror(FM)samplesmadeofpolycrystalline(PC)stainlesssteel(SS),molybdenum(Mo)andtungsten(W)werefixedonaholderatanangleof45withrespecttothehorizontalplaneandsetatdifferentlocationswithdifferentconnectionlengthsalongthemagneticfield.Theopticalreflectivityofthefirstmirrorwasmeasuredbyaspectrophotometerbeforeandafterplasmaexposure.Itwasfoundthatthesurfacemorphologyandspecularreflectivityofthemirrorsamplesaftertheexposureweredifferentwithrespecttothedifferentdistancesfromthemirrorsurfacetothelastclosedfluxsurface(LCFS)oftheplasmainthetokamak.Itwasalsofoundthatshorteningtheconnectionlengthbeforethemirrorsurfacewouldweakentheinfluenceoftheplasmaerosionandimpuritydepositiononthemirrorsurface.Inordertomaintaintheopticalcharacteristicsofthemirrorsurface,itisnecessarytoadoptthein-situcleaningandmirrorprotectiontechniques.
简介:Inlowerhybridcurrentdrive(LHCD)experimentsinHT-7,LHwavecoupledtotheplasmafrom12klystronsislaunchedbyaphasedmulti-junctiongrill.Highpowermicrowavereflectionorarc,whichthreatenstheklystrons,thewave-guideceramicwindowsandthevacuumofthetokamak,occursometimesduringtheexperiments.Forthesakeofsafety,ahighpowermicrowavetestsystemtoperformsimulationswasdeveloped.Inthetestexperiments,theklystronandwindowcanbewellprotectedwithanoptimizedmicrowavemonitorandaPINswitch.ThelayoutofthetestsystemandthesimulatedexperimentsforHT-7aredescribedinthispaper.
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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:Inthiswork,aplasma-solutionsystemwasappliedtothedegradationofAcidOrange7(A07).Theeffectsofinitialconcentrationandtypeoffeedgases(air,oxygen,nitrogenorargon)werestudied.Astheinitialconcentrationincreasedfrom100mg/Lto160mg/L,thediscolourationrateofA07decreasedfrom99.3%to95.9%,whereastheCODremovalratedecreasedfrom37.9%to22.6%.AirprovidedthebestdiscolourationandCODremovalrates(99.3%and37.9%,respectively).Inthepresenceofazero-valentiron(ZVI)catalyst,theA07CODremovalrateincreasedto76.4%.ThedegradationproductswereanalysedbyaGC-MS,revealingthatthedegradationofthedyemoleculewasinitiatedthroughthecleavageofthe-N=N-bondbeforefinallybeingconvertedtoorganicacids.
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简介:本文通过高分辨X射线衍射及掠入射(GID)的实验方法对生长在SrTiO3衬底上的LLa2/3Ca1/3MnO3和YBaCu3O7单层膜及YBa2Cu3O7-x/La2/3Ca1/3MnO3异质结构双层薄膜的微结构进行了研究。结果发现,所有薄膜都呈c向生长。由于热膨胀系数的不同而引起的热应力使得LCMO膜的晶格参数与靶材的相差较大。La2/3Ca1/3MnO3在单层腹及双层膜中都由靶材的立方结构变成了薄膜状态的四方结构。YBa2Cu3O7在单层膜及双层膜中都由靶材的正交结构变成了薄膜状态的四方结构。La2/3Ca1/3MnO3膜与YBa2Cu3O7膜在不同的样品中处于不同的应力状态。