It is shown that one should take into account rather small radiation penetration length in metal (Al) to describe properly nanosecond laser induced explosive (volume) boiling process. The result is obtained in the framework of molecular dynamic simulations combined with continual description of metal electron subsystem. Absorption of intense electromagnetic pulses gives rise to various nonequilibrium processes in condensed matter which result in ablation of irradiated materials. These processes are investigated theoretically and experimentally for many decades (see, e.g., [1–9] and references therein). However, some of the problems in laser ablation are not yet completely resolved. Laser-matter interaction depends on laser pulse intensity and duration as well as on electromag- netic properties of irradiated samples. For metals optical radiation penetration length is usually rather small. For this reason and because of high values of metal thermal conductivity appearance of explosive (volume) boiling in metals irradiated with intense electromagnetic pulses is not evident beforehand in usual continual description of laser-metal interaction which is briefly depicted be- low. Steady state equation for temperature distribution T (z) in evaporated sample (Al) (halfspace z > 0) has a form [1]: ∂T ∂2T αI V +χ 2 + exp(−αz) = 0 ∂z ∂z ρc ¯ ∂T ¯¯ (1) cχ = LV, ∂z ¯0 T (t, ∞) = T∞ where the density ρ, heat capacity c, thermal diffusivity χ and absorption coefficient α are assumed to be constant. From (1) it follows: · µ ¶¸ V Tst = T∞ + ∆T A exp(−αz) + B exp − z , χ (2) A = V (c∆T + L) / (c∆T (V − αχ)) , B = 1 − A, ∆T = T0 − T∞ I = ρV (L + c∆T ) (3) Vaporization velocity V and heat of evaporation L depend on surface temperature Ts : r p m V = 0.83 , p(Ts ) = pb · exp (11.5 · (1 − Tb /Ts )) (4) ρ0 2πkTs where p — saturation pressure at surface temperature Ts , Tb = 2792 K is normal boiling tempera- ture, pb = 1 bar, m — mass of the evaporated particles, k is Boltzmann constant Figure 1 shows temperature distributions T (z) for two different intensities and α = 0.7·106 cm−1 . The distributions demonstrate that the surface temperature Ts is somewhat lower then the max- imum temperature Tm . For metals with high values of α and χ relation (Tm − Ts )/Tm ¿ 1 is rather small even at high temperatures where V approaches its maximum value. For this reason in some papers [2, 3] it is argued that this difference can be neglected. However, our recent investiga- tions [4–6] show that it is this temperature difference which gives rise to explosive (volume) boiling in the subsurface region where additional subsurface superheating occurs. Progress In Electromagnetics Research Symposium Proceedings 2419