Fourth-order fractional diffusion model of thermal grooving: integral approach to approximate closed form solution of the Mullins model

Abstract

A multiple integration technique of the integral-balance method allowing solving high-order subdiffusion diffusion equations is presented in this article. The new method termed multiple-integral balance method (MIM) is based on multiple integration procedures with respect to the space coordinate. MIM is a generalization of the widely applied Heat-balance integral method of Goodman and the double integration method of Volkov. The method is demonstrated by a solution of the linear subdiffusion model of Mullins for thermal grooving by surface diffusion.