Refraction of reaction-diffusion plane wave for different diffusion coefficients

The effect of diffusion on the refraction of plane wave in two-dimensional reaction-diffusion system described by complex Ginzburg-Landau equation are numerically investigated. We derive the refractive index of plane wave from Snell's law. The numerical and theoretic results show that the refraction of plane wave in a simple purely diffusive system obeys Snell's law, i.e, diffusion only impacts the refractive index of plane wave. However, the refraction of plane wave in reaction-diffusion system obeys Snell's law only for proper diffusion coefficients and system parameters. These results show that diffusion impacts the refraction law and refractive index.