EGAM induced by energetic electrons and nonlinear interactions among EGAM, BAEs and tearing modes in a toroidal plasma

► The EGAM has been recently observed for the first time on HL-2A. ► The EGAM is most probably excited by energetic electrons via the three wave resonance and precessional resonance. ► There exist intense nonlinear interactions among EGAM, BAEs and strong TMs.