Effect of ion nonthermality on nonlinear dust acoustic wave propagation in a complex plasma in presence of secondary electron emission

In this paper we have investigated the effect of ion nonthermality on nonlinear dust acoustic wave propagation in a complex plasma in presence of secondary electron emission considering equilibrium dust charge positive. In space and astrophysical plasmas presence of nonthermal ions have been detected by satellite observations. This ion nonthermality modifies propagation characteristics of dust acoustic waves when dust grains are charged by secondary electron emission mechanism. In case of dust charging by secondary electron emission process two stable equilibrium dust charge states exist out of which one is negative and the other is positive. Here we have considered positive equilibrium dust charge state and both adiabatic and nonadiabatic dust charge variation. Our investigation shows that characteristics of both dust acoustic soliton and dust acoustic shock depend on the strength of the ion nonthermality along with secondary electron yield. Increase in both ion nonthermality and secondary electron yield help to retain the shape of compressive dust acoustic soliton when dust charge variation is adiabatic and to maintain oscillation of the dust acoustic shock when dust charge variation is nonadiabatic.