Simulation of Shrapnel to Aid in the Design of NIF/LMJ Target-Diagnostic Configurations

Shrapnel fragments, produced when target/diagnostic components are impulse loaded, can reduce the lifetime of final optical components. The authors give simulations results of shrapnel generation in thin metal plates loaded by laser heating. They discuss two approaches to predicting the size and velocity distribution of the shrapnel fragments. The first uses the 2D LASNEX code to calculate energy absorption, shock propagation, and material response. The calculated strain rates combined with hydrodynamic quantities are used to determine properties of the fragments. The second uses the 1D DELPOR code to calculate energy absorption with the results coupled to the 3D HESIONE code to calculate dynamic fragmentation. They show results of varying the incident laser energy and the plate material. They compare with data obtained using low-density aerogel to capture shrapnel fragments.