Ioncyclotronrangeoffrequency(ICRF)heatinghasbeenusedintokamaksasoneofthemostsuccessfulauxiliaryheatingtoolsandhasbeenadoptedintheEAST.However,theantennaloadwillfluctuatewiththechangeofplasmaparametersintheICRFheatingprocess.ToensurethesteadyoperationoftheICRFheatingsystemintheEAST,fastferritetuner(FFT)hasbeencarriedouttoachievereal-timeimpedancematching.FortherequirementsoftheFFTimpedancematchingsystem,themagnetsystemoftheferritetuner(FT)wasdesignedbynumericalsimulationsandexperimentalanalysis,wherethebiasingmagneticcircuitandalternatingmagneticcircuitwerethekeyresearchedpartsoftheferritemagnet.TheintegraldesigngoaloftheFTmagneticcircuitisthatDCbiasmagneticfieldis2000Gsandalternatingmagneticfieldis±400Gs.IntheFTT,E-typemagneticcircuitwasadopted.FerritematerialisNdFeBwithathicknessof30mmbysettingtheworkingpointofNdFeB,andtheampereturnofexcitationcoilis25throughthetheoreticalcalculationandsimulationanalysis.Thecoilinductancetogeneratealternatingmagneticfieldisabout7mH.Eddy-currenteffecthasbeenanalyzed,whilethemagneticfielddistributionhasbeenmeasuredbyaHallprobeinthemediumplaneofthebiasingmagnet.Finally,thetestresultsshowthegoodperformanceofthebiasingmagnetsatisfyingthedesignandoperatingrequirementsoftheFFT.
