Global boundedness and asymptotic behavior of time-space fractional nonlocal reaction-diffusion equation

TL;DR

This paper investigates the global boundedness and long-term behavior of solutions to a time-space fractional nonlocal reaction-diffusion equation, establishing existence, boundedness, and convergence results under various conditions.

Contribution

It provides new existence and boundedness results for solutions of the fractional nonlocal reaction-diffusion equation, including cases with different spatial dimensions and specific nonlinearities.

Findings

Global bounded weak solutions exist for N=1.

For N=2, solutions are bounded for large k values.

Solutions decay to zero exponentially or locally uniformly over time.

Abstract

The global boundedness and asymptotic behavior are investigate for the solution of time-space fractional non-local reaction-diffusion equation (TSFNRDE) $$ \frac{\partial^{\alpha }u}{\partial t^{\alpha }}=-(-\Delta)^{s} u+\mu u^{2}(1-kJ*u)-\gamma u, \qquad(x,t)\in\mathbb{R}^{N}\times(0,+\infty),$$ where $s\in(0,1),\alpha\in(0,1), N \leq 2$. The operator $\partial_{t}^{\alpha }$ is the Caputo fractional derivative, which $-(-\Delta)^{s}$ is the fractional Laplacian operator. For appropriate assumptions on $J$, it is proved that for homogeneous Dirichlet boundary condition, this problem admits a global bounded weak solution for $N=1$, while for $N=2$, global bounded weak solution exists for large $k$ values by Gagliardo-Nirenberg inequality and fractional differential inequality. With further assumptions on the initial datum, for small $\mu$ values, the solution is shown to converge to $0$ exponentially or locally uniformly as $t \rightarrow \infty$. Furthermore, under the condition of $J \equiv 1$, it is proved that the nonlinear TSFNRDE has a unique weak solution which is global bounded in fractional Sobolev space with the nonlinear fractional diffusion terms $-(-\Delta)^{s} u^{m}\, (2-\frac{2}{N}<m<1)$.