Heating of metals at a free surface by laser irradiation—an electron kinetic theory approach

Abstract

Application of Fourier theory to heat conduction due to laser irradiation at high power intensities (i.e. 1010 W/m2) gives errors of the order of 30 per cent at the upper end of the temperature rise time. This is caused by the assumptions made in the Fourier theory, since the heat flux through a given plane depends on the electron energy distribution through the material. On the scale of distance required to examine the problem, the material can no longer be considered as being a homogeneous continuum and when the power intensities of interest are concerned, the higher order terms in the heat transfer equation become important. Therefore, the problem requires to be examined in the quantum field. Application of electron kinetic theory to the problem enhances the solution within an accuracy greater than 90 per cent. The present theory introduces a new model for the conduction mechanism.