Cluster-induced crater formation

Using molecular-dynamics simulation, we study the crater volumes induced by energetic impacts (v=1–250km/s) of projectiles containing up to N=1000N=1000 atoms. We find that for Lennard–Jones bonded material the crater volume depends solely on the total impact energy EE. Above a threshold EthEth, the volume rises linearly with EE. Similar results are obtained for metallic materials. By scaling the impact energy EE to the target cohesive energy UU, the crater volumes become independent of the target material. To a first approximation, the crater volume increases in proportion with the available scaled energy, V=aE/UV=aE/U. The proportionality factor aa is termed the cratering efficiency and assumes values of around 0.5.