Dynamics of colliding ablation plumes

Carbon and tungsten have been radiated by 3ω-YAG laser in the power density range from 2 to 12J/cm/pulse in a laboratory setup with the main objective of investigating the behavior of cluster/aerosol formation from colliding ablation plumes. Direct ion mass spectrometry of colliding carbon plumes has identified Cn-clusters including C, C2,C3,C4 and C5. The formation of these Cn-cluster ions has been found to favor relatively low laser power densities. From timing-controlled Langmuir probe measurements for carbon and tungsten, the density decay constants for single plumes have been found to be 1.2μs and 4.4μs, respectively, whereas colliding plumes have been evaluated to be 1.4μs and 5.3μs.