Experimental study of core-localized TAEs during ICRF heated high <i>β</i> _p plasmas on EAST

Abstract This study presents the first experimental investigation of core-localized Toroidal Alfvén eigenmodes (TAEs) during high- β p plasmas heated purely by radio frequency waves (particularly ion cyclotron resonance frequency) on EAST. The results reveal a power threshold for TAE excitation, with TAE activity significantly influenced by plasma density and neutral beam injection (NBI): increased density reduces TAE frequency and eventually suppresses the modes, while NBI inhibits TAEs by altering the fast-ion distribution. Additionally, sawtooth oscillations selectively enhance or suppress different TAE modes through fast-ion redistribution. Although the diagnostics could not directly resolve core-localized modes due to coverage limitations, simulations suggest that high-frequency TAEs exhibit stronger core localization, whereas the dominant TAE mode displays broader radial extension. No observable detrimental effects on plasma confinement were found. TAEs were observed under plasma conditions associated with relatively higher neutron yields, reflecting the presence of a strong fast-ion population. These findings provide important insights for TAE excitation and control in future fusion devices.