Pulsed laser evaporation: equation-of-state effects
Pulsed laser evaporation: equation-of-state effects
复制标题
脉冲激光蒸发：状态方程效应
DOI：
10.1007/s003390051041
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发表时间：
1999
期刊：
影响因子：
--
通讯作者：
V. Fortov
中科院分区：
文献类型：
--
作者：
S. Anisimov;N. Inogamov;A. Oparin;B. Rethfeld;T. Yabe;M. Ogawa;V. Fortov
摘要：激光烧蚀的理论研究通常是基于蒸汽是理想气体的假设。其流动由气体动力学方程描述[1，2]。汽化前沿的边界条件来自玻尔兹曼方程的解，玻尔兹曼方程描述了汽化表面（所谓的努森层）附近的蒸汽流动[1]。该模型适用于远低于靶材临界温度的温度范围。在目前的工作中，一般情况下，被认为是当冷凝相的温度是可比的或高于临界温度。在这种情况下，凝聚相和气相的动力学都可以用流体力学方程来描述。用解析和数值方法研究了超短激光脉冲加热金属的汽化动力学。分析表明，流动由两个区域组成：薄的液体壳层以恒定的速度运动，和厚的低密度层的两相状态的材料。
Abstract.Theoretical study of laser ablation is usually based on the assumption that the vapor is an ideal gas. Its flow is described by gas dynamics equations [1, 2]. The boundary conditions at vaporization front are derived from the solution of the Boltzmann equation that describes the vapor flow in the immediate vicinity of the vaporizing surface (so-called Knudsen layer) [1]. This model is applicable within the range of temperatures much lower than the critical temperature of target material. In the present work, a general case is considered when the temperature of the condensed phase is comparable to or higher than the critical temperature. The dynamics of both condensed and gaseous phases can be described in this case by the equations of hydrodynamics. The dynamics of vaporization of a metal heated by an ultrashort laser pulse is studied both analytically and numerically. The analysis reveals that the flow consists of two domains: thin liquid shell moving with constant velocity, and thick low-density layer of material in two-phase state.