The phenomena in short pulsed laser irradiation to a pure aluminum substrate are analyzed on the basis of thermohydrodynamics to evaluate the mechanism of bump formation in laser texturing for a magnetic disk. The analysis model is made for calculation of surface profile, temperature field and velocity field assuming that the vaporization recoil pressure, surface tension and thermocapillay force (Marangoni effect) act at the free surface with taking account of the evaporated mass loss. It is found that a crater shape bump is formed by the flow induced by the vaporization recoil pressure mainly and that thermocapillary force makes a bump higher while outside of bump-formed area starts to solidify.

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