Role of infernal modes dynamics and plasma rotation on the onset of NTMs in ECH-ECCD TCV plasmas

摘要

ExperimentsintheTCVtokamakshowthatwhenhighpowercentralelectroncyclotronheating(ECH)andcurrentdrive(ECCD)aredepositedinthecentralplasmaregion,tearing-likeinstabilitiescandevelop.Inthepresentworkweaddress,bothanalyticallyandnumerically,theproblemoftearingmode(TM)generationanalysingextensivelythebehaviourofL-modeandlowplasmacurrentTCVdischargeswhenhighpowerheatingisdepositedintheplasmacoreregion.Threepossiblemechanismsarediscussed.ThefirstisthemodificationoftheequilibriumcurrentdensityprofileduetothepowerdepositionleadingtovariationofthesignoftheclassicaltearingstabilityindexΔ',wherefiniteβeffectscouldalsobetakenintoaccount.ThesecondmechanismstillthemodificationofthetearingstabilityparameterΔ',butthistimeduetothepresenceofanequilibriumshearedtoroidalplasmarotation.Finally,thethirdmechanismconsideredistheroleofinfernal-typeinstabilitiesindrivingtearing-likemodeswhenthesafetyfactorbecomessufficientlyclosetoarationalinthecoreregion...