Fig. 1. Effects of plasma density η and electron temperature f on nonlinear frequency shift coeffcient L and second harmonic coeffcient A_2φ for k = 0.25

Fig. 2. Effect of plasma density η, electron temperature f, the first harmonic amplitude φ₁ and wave number k on nonlinear frequency shift

Fig. 3. Variation of nonlinear frequency shift with electron temperature f for k = 0.25