Symmetries and approximate solution of energy transfer equations in short pulse laser heating

Energy transfer equations in laser heating are considered. Symmetries of the equations are calculated by Lie Group theory. Using the symmetries, the equations are transferred to an ordinary differential system. Equations are approximately solved by strained parameter method, a perturbation technique. A boundary value problem in which the laser beam transfers heat to the surface is treated. Closed form approximate solutions for electron and lattice site temperature rise are obtained for a solid layer heated at the surface with a time decaying intensity pulse. Analytical solutions are verified by numerical simulations.