简介:SawtoothcontrolexperimentswereperformedonHT-7withalimiterconfigurationandontheExperimentalAdvancedSuperconductingTokamak(EAST)withadoublenullcon-figuration.Thesawtoothperiodcanbemodifiedbylowerhybridwave(LHW)andioncyclotronresonancefrequency(ICRF).Differentsawtoothbehaviorwasobservedwiththesameplasmadensity,LHWpowerbutdifferentplasmacurrentsonHT-7.TherewasadwelltimebetweenLHWaddedandthesawtoothstabilizationonHT-7whilethesawtoothstabilizationimmediatelyhappenedwhenLHWpowerwasinjectedonEAST.Thepossiblemechanismofthesawtoothcontrolisdiscussedinthispaper.Alltheexperimentalresultshaveprovedthatpowerdepositionoftheradiofrequency(RF)shouldbethekeyfactorforsawtoothcontrol.
简介:Duty-cyclemodulationalternatelyblowingfromtwoopposite-facingplasmaactuatorsontheleewardsurfaceneartheapexofaconewitha10semi-apexangleisadoptedtocontrolmeanlateralforceandmoment,andtheflowcontrolmechanismsarepresented.Pressuredistributionsovertheforebodyoftheconearemeasuredbysteadypressuretappings.Theexperimentsareperformedina3.0×1.6mopen-circuitwindtunnelatawindspeedof20m/s,a45angleofattackandaReynoldsnumberof2×105,basedonthediameterofthebaseofthecone.Almostlinearlyproportionalcontrolofthelateralforcesandmomentsoveraslenderconicalforebodyatahighangleofattackhasbeendemonstratedbyemployingapairofsingledielectricbarrierdischargeplasmaactuatorsneartheapexofthecone,combinedwithaduty-cycletechnique.Thepressuredistributionmeasurementsindicatethatthebi-stablevortexpatternappearstobeshiftedintheoppositedirectionwhentheportorstarboardactuatorisactivated,whiletheotheriskeptoffduringthetest.Itisshownthatthereducedpulse-repetitionfrequencybasedonthelocaldiameterattheplasmaactuatorequaltooneyieldsthehighesteffectivenessamongthecasesconsidered.