Research on fast relaxing temperature excitations caused by ultrashort laser pulses

Eremin Anton Vladimirovich

By using a modified Fourier law’s formula which considers the relaxation of heat flow and temperature gradient, a mathematical model of local non-equilibrium process of plate heating by ultra short laser pulses modeled by a time-variable second-class boundary condition (heat flow is the step time function) taking into account its local non-equilibrium was developed. Numerical studies of the model showed that consideration of local non-equilibrium of the heat exchange process results in a delay in setting boundary conditions (irrespective of their type) due to the resistance caused by the medium studied to the process of heat propagation. Consideration of local non-equilibrium of the pulsed second-class boundary condition results in the smoothing of temperature jumps in the surface layer of the plate. The depth of the heated layer for each heat flow power has a definite value that remains constant over time.

Keywords:boundary problem, locally non-equilibrium heat exchange, pulsed heat flow, heat flow relaxation, relaxation coefficients, numerical solution, analytical solution