Traveling waves for a two-phase Stefan problem with radiation

In this paper we study the existence of traveling wave solutions for a free-boundary problem modeling the phase transition of a material where the heat is transported by both conduction and radiation. Specifically, we consider a one-dimensional two-phase Stefan problem with an additional non-local non-linear integral term describing the situation in which the heat is transferred in the solid phase also by radiation, while the liquid phase is completely transparent, not interacting with radiation. We will prove that there are traveling wave solutions for the considered model, differently from the case of the classical Stefan problem in which only self-similar solutions with the parabolic scale $x\sim \sqrt{t}$ exist. In particular we will show that there exist traveling waves for which the solid expands. The properties of these solutions will be studied using maximum-principle methods, blow-up limits and Liouville-type Theorems for non-linear integral-differential equations.