Photoinduced local nonequilibrium states in superconductors: hot spot model

The so-called hot spot model is often used to study problems concerning the local heating of electrons and phonons and local suppression of superconductivity by electromagnetic radiation. This model implies that the dynamics of a system in a certain time interval can be described by a locally equilibrium electron distribution function, but the electron temperature $T_e$ differs from the equilibrium value. Such an assumption makes it possible to use the heat equation to study the temporal and spatial dynamics of $T_e$ and significantly simplifies the study of the dynamic response of a superconductor. Examples of the use of this model to describe nonequilibrium effects occurring in systems with different types of superconducting pairing under electromagnetic irradiation have been presented in this work.