The propagation of electron-acoustic waves (EAWs) in plasmas composed of inertial cold electrons, hot superthermal electrons, and stationary ions is investigated. By means of the reduction perturbation technique, a nonlinear Schrödinger equation is derived and the modulation instability of EAW is analyzed, where the superthermal parameter is found to be of the significant importance. It is shown that the presence of superthermal electrons enhances the critical wave number of the modulational instability of EAWs. Besides, due to the presence of the superthermal electrons, EAWs are stable on a vaster region. Moreover, the modulational instability growth rate is lower for a larger population of superthermal electrons. Further, it is shown that increasing values of the relative density ratio a = ne0/nc0 shifts the instability domain to lower values of wave number k.

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