Entropy analysis and improved formulation of electron kinetic theory approach for laser short-pulse heating

摘要

Laser short-pulse heating of matallic substrates triggers nonequilibrium energy transport in the region irradiated by a laser beam. Entropy analysis gives information on the energy transport process during the laser short-pulse heating process. In the present study, formulation of entropy production in the electron and lattice subsystems as well as their coupling through thermal communication of these subsystems is carried out. The ballistic behavior of the excited electrons in the electron subsystem is also considered. The temperature fields obtained from previously developed and improved electron kinetic theory approaches and two-equation models are compared. It is found that entropy production during thermal communication of electron and lattice subsystems is higher than those corresponding to electron and lattice subsystems.