Decay rates of solutions to the Cauchy problem for dissipative nonlinear evolution equations Original Research Article

In this paper, we study the global existence and the asymptotic behavior of the solutions to the Cauchy problem for the following nonlinear evolution equations with ellipticity and dissipative effects equation(E) View the MathML source{ψt=−(1−α)ψ−θx+αψxx,θt=−(1−α)θ+νψx+(ψθ)x+αθxx, Turn MathJax on with initial data equation(I) View the MathML source(ψ,θ)(x,0)=(ψ0(x),θ0(x))→(ψ±,θ±)as x→±∞, Turn MathJax on where αα and νν are positive constants such that α<1α<1, ν<α(1−α)ν<α(1−α). Through constructing a correct function View the MathML sourceθˆ(x,t) defined by (2.13) and using the energy method, we show supx∈R(|(ψ,θ)(x,t)|+|(ψx,θx)(x,t)|)→0supx∈R(|(ψ,θ)(x,t)|+|(ψx,θx)(x,t)|)→0 as t→∞t→∞ and the solutions decay with exponential rates. The same problem was studied by Tang and Zhao [S.Q. Tang, H.J. Zhao, Nonlinear stability for dissipative nonlinear evolution equations with ellipticity, J. Math. Anal. Appl. 233 (1999) 336–358] for the case of (ψ±,θ±)=(0,0)(ψ±,θ±)=(0,0).