简介:Itisoftenstatedthatevencleantokamakdischargesdisruptathighdensity.Onepossibilityisthatsuchdisruptionresultfromtheenergylossarisingfromhydrogenrecyclingattheedgeoftheplasma.thisenergylosscouldleadtoacontractionofthecurrentchannelandtheproductionofadisruptivelyunstableconfiguration.
简介:StableoperatingregionintheHL-1Mtokamakhasbeenextendedbymeansofwallconditioning,corefuellingandcurrentcontroltechniques.Themechanismsoftheextensionareanalyzedinthispaper.Lithiumizationdiminishestheimpuritiesandhydrogenrecyclingtothelowestlevel.Afterlithiumizationahighdensityupto7×1019m-3wasobtainedeasilybystronggaspuffingwithordinaryohmicdischargealone.MoreattractivelywefoundthatmetalLi-coatingexhibitedtheeffectsofwallstabilization.Thelowqalimitwithhigherdensitywasextendedbyafactorof1.5~2incomparisonwiththatforboronization,and1.2forsiliconization.Siliconizationnotonlyextendedstableoperatingregionsignificantlybyitself,butalsoprovidedagoodtargetplasmaforotherexperimentsofraisingdensitylimit.Corefuellingschemesarefavourableespeciallyforsiliconizedwallwithahigherlevelofmedium-Zimpurity(Z=14).Aftersiliconizationthemaximumdensitynearto1020m-3wasachievedbyacombinationofsupersonicmoleculebeaminjectionandmultipelletinjection.ThenewdefinedslopeofHugilllimitillustratingmoreclearlythesituationunderlowqaandhighnedischargeswascreatedtoindicatethenewregionextendedbycombiningIpramp-upwithcorefuelling.TheslopewithalargeMurakamicoefficientincreasedbyafactorof50~60%.
简介:Theobservedlossrateofbothparticlesandenergyfromhotconfinedtoroidalplasmasismuchhigherthantheonepredictedbyneoclassicaltransporttheory,whichdependsuponmeanplasmaparametersandCoulombcollisions.Manytypesofplasmaturbulencehavebeenproposedtoexplainanomalousplasmatransport.Thefluctuationofplasmaparametersaroundtheirmeanvaluescancausetransportthroughelectrostaticormagneticfluctuations.Thefluctuationdrivenradialparticlefluxisgivenby
简介:RecentexperimentalresultsofHL-1MtokamakandprogressofHL-2Aprojectarepresented.Strongfishboneinstabilitywasobservedduringoff-axisECRH.ThisisfirstobservationofthefishboneinstabilitypurelydrivenbyenergeticelectronsproducedbyECRH.TheMBIwasfirstproposedanddemonstratedonHL-1M.RecentlynewresultsofMBIexperimentwereobtainedbyincreasingthepressureofgas.Astair-shapedensityincrementwasobtainedwithhigh-pressuremulti-pulseMBIjustlikethedensityevolutionbehaviorduringthemultipelletinjection.Itisshown
简介:Thescalinglawsofenergyconfinementareverysignificantforconfinementimprovement.AtypicalscalinglawofohmicheatingwithloweffectivechargeandradiationpowerisgivenbyGoldston
简介:Pelletinjectionexperimentshavebeenwidelycarriedoutwithvarioustoroidalplasmas,peakeddensityprofileandimprovedconfinementarefrequentlyobserved,andsomeinterestingphenomenahavealsobeenfound.Oneofthemisthelong-livedm=1/n=1oscillationobservedonsoftX-rayemissionandotherdiagnostics(notablythemicrowaveinterferometersandtheECEsystems)afterpelletinjectioninJET,JT-60,
简介:Aneight-shotspelletinjection(PI)andasupersonicmolecularbeaminjection(SMBI)systemhaveproposedanddevelopedontheHL-1Mtokamakforadvancedfuellingexperiments.ThepeakeddensityprofileandimprovedconfinementaretypicalfeatureofPIandSMBIdischarge.ItstronglydependsonthewallrecyclingconditionsoftheHL-1Mtokamakandinjectionparameters.
简介:IntheHL-1Mplasmaexperiments,tworefuelingways,thepelletinjectionandthegaspuffing,areusuallyused.Inrecentyears,anewrefuelingmethod,thesupersonicmoleculebeam(SMB)injection,hasbeendeveloped.SMBinjectionisanattempttoenhancethepenetrationdepthandthefuellingefficiencyofgas,aswellastoreducesurfaceabsorptionoftheinjectedparticlesandtheimpuritycontentintheplasma.InSMBinjectionexperiments,thegasisinjectedintotheplasmathroughaLavalnozzleathighgaspressure.Inthiscase,thepeakdensityandimprovingconfinementhavebeenachievedasinthecaseofapelletinjection.
简介:Anomaloustransportisoneofthemostimportantsubjectsforthetokamakresearch.Experimentshaveconfirmedthatanomaloustransportiscausedbyturbulencesdrivenbytemperatureanddensitygradientinplasma.Theexperimentsshowthationdiffusioncanbereducedtoneoclassicallevelinhighparameterplasmawithinternaltransportbarrier.
简介:TheMHDinstabilitiesintheplasmacentrecanbeobservedwithpinholecamerastorecordsoftX-ray(SXR)emissionalongmanychordswithhighspeatialresolution.ThesoftX-raysystemintheHL-1Mtokamakconsistsofthreepinholecameraswith60chords.Themethodofsingularvaluedecomposition(SVD)cansplitsuchsignalsintoorthogonalspatialandtemporalvectors.Bythismeans,
简介:Recently,theL-modetoH-mode(L-H)transitionintokamakplasmaconfinementwasfoundtoberelatedtothepresenceofthepoloidalflowshearneartheplasmaedge.Animportantmechanismistheionorbitlosscausedbyinteractionwiththelimiter.AcomplementaryexplanationisthegenerationofpoloidalflowsbyplasmafluctuationsviatheReynoldsstressandthepoloidalspin-upofplasmasfrompoloidalasymmetryofparticleandmomentumsources.
简介:Inthecontemporarylargetokamak,thedisruptiveterminationofadischargewillreducethelifetimeofthefirstwallmaterialswiththeintenseheatfluxattheenergyquenchandtheintenserunawayelectronsduringthecurrentquench,andgeneratehighelectronmagneticforcesonvacuumvesselcomponentswithintenseeddycurrentatthecurrentquench.Thus,avoidanceandsofteningoftheenergyquenchandthecurrentquenchandcontrollinganexpecteddisruptionoremergencyshutdownmustbeestablishedinthepresenttokamakmachines.