Keywords: 
• 物理机制 /
• 熔化 /
• 皮秒激光脉冲 /
• 校正分子动力学

Abstract: The kinetics and microscopic mechanisms of ultrashort laser melting of a copper film is studied by modified molecular dynamics method.A model considering the thermal conductivity of free electrons and the consumption of latent heat of melting is used to make the simulation more realistic.The mechanism responsible for the melting of copper under picosecond laser pulse irradiation can be attributed to the homogeneous nuclea-tion of the liquid phase inside the solid region.The melting is a overheated melting caused by homogeneous nu-cleation.and the velocity of propagation of"melt front"is found up to be 5.8 nm/ps.Picosecond laser pulse in-duced melting occurring under the condition of thermal confinement results in a less complicate temperature dis-tribution and a weaker effect of unloading wave on stress wave compared with those in stress confinement re-gion.