Simulation of initiation of PETN by a nanosecond laser pulse in the weak absorption region

A numerical simulation of the initiation of PETN by a laser pulse was performed. The heat-conduction equation was solved in a cylindrical coordinate system taking into account multiple reflection of the light beam, zero-order exothermic reaction, and melting. A criterion for the ignition of explosives by a laser pulse with multiple reflection of the light flow was obtained. The calculation results are in satisfactory agreement with experiment and the ignition criterion. Dependence of the critical energy density on the light beam radius is due to radial heat transfer. The ignition threshold can be controlled by changing the reflection coefficient of the back surface of the sample.