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Large-scale structures produced on metal surfaces by multiple laser pulses

A mathematical model is constructed to describe the formation of inhomogeneous surface structures 10–50 μm in height on metal surfaces exposed to repetitive laser pulses with the following parameters: pulse duration of ∼20 ns, pulse repetition rate of ∼10 kHz, pulse intensity in the range 107—108 W cm-2 and beam diameter from 50 to 100 μm. The model takes into account melting of the metal and melt flow over a distorted surface. The surface profile amplitude evaluated in the model agrees with experimental data.