Atomistic simulation of the transition from atomistic to macroscopic cratering

Using large-scale atomistic simulations, we show that the macroscopic cratering behavior emerges for projectile impacts on Au at projectile sizes between 1000 and 10000 Au atoms at impact velocities comparable to typical meteoroid velocities. In this size regime, we detect a compression of material in Au nanoparticle impacts similar to that observed for hypervelocity macroscopic impacts. The simulated crater volumes agree with the values calculated using the macroscopic crater size scaling law, in spite of a downwards extrapolation over more than 15 orders of magnitude in terms of the impactor volume. The result demonstrates that atomistic simulations can be used as a tool to understand the strength properties of materials in cases where only continuum models have been possible before.