Effects of the Second Harmonic on the Geodesic Acoustic Mode in Electron-Temperature-Gradient Turbulence Johan Anderson 1 , Hans Nordman 1 and Raghvendra Singh 2,3 1 Dept. Earth and Space Sciences, Chalmers University of Technology, SE-412 96 G¨oteborg,Sweden 2 WCI, Daejon, South Korea 3 Institute for Plasma Research, Bhat, Gandhinagar, Gujarat, India 382428 E-mail: anderson.johan@gmail.com Abstract. The effects higher order harmonics have been self-consistently included in the derivation of the electron branch of the electron Geodesic Acoustic Mode (el-GAM) in Electron-Temperature-Gradient (ETG) turbulence background. The work is based on a two-fluid model including finite β-effects while retaining non-adiabatic ions. In solving the linear dispersion relation, it is found that the due to the coupling to the m = 2 mode the real frequency may be significantly altered and yield higher values. PACS numbers: 52.55.-s, 52.35.Ra, 52.35.Kt