Superconvergence analysis of finite element method for time-fractional Thermistor problem

In this paper, the superclose and superconvergence analysis of the nonlinear time-fractional thermistor problem are investigated by bilinear finite element method (FEM) for a fully-discrete scheme, in which the Caputo derivative is approximated by the classical L1 method. By dealing with the error estimates in the spatial direction rigorously, which are one order higher than the traditional FEMs, the superclose estimates in H1-norm are obtained for the corresponding variables based on the special properties of this element together with mean value technique. Subsequently, the global superconvergence results are derived by employing the interpolation postprocessing approach. Finally, a numerical experiment is carried out to confirm the theoretical analysis.