  Zero frequency zonal flow (ZFZF) excitation by trapped energetic electron
driven beta-induced Alfven eigenmode (eBAE) is investigated using nonlinear
gyrokinetic theory. It is found that, during the linear growth stage of eBAE,
resonant energetic electrons (EEs) not only effectively drive eBAE unstable,
but also contribute to the nonlinear coupling, leading to ZFZF excitation. The
trapped EE contribution to ZFZF generation is dominated by EE responses to eBAE
in the ideal region, and is comparable to thermal plasma contribution to
Reynolds and Maxwell stresses.
