A new model for studying the plasma plume expansion property during nanosecond pulsed laser deposition
A new model for studying the plasma plume expansion property during nanosecond pulsed laser deposition
复制标题
研究纳秒脉冲激光沉积过程中等离子体羽流膨胀特性的新模型
DOI：
10.1088/0022-3727/41/3/035210
复制
发表时间：
2008-02-07
影响因子：
3.4
通讯作者：
Fang, Ranran
中科院分区：
文献类型：
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作者：
Tan, Xinyu;Zhang, Duanming;Fang, Ranran
建立了一个研究纳秒脉冲强激光辐照材料时激光诱导等离子体动力学膨胀的物理模型。在考虑等离子体电离效应和局部质量、动量、能量守恒的基础上，结合等离子体可以看作可压缩理想流体和高温高压理想气体的假设，提出了一种新的脉冲激光等离子体动力学膨胀机制.在此基础上推导了一组新的等离子体膨胀动力学方程。然后，以碳靶为例，采用有限差分法，详细研究了等离子体进入真空的动力学过程，包括等离子体空间数密度分布、等离子体数密度以及径向和轴向速度的演化。结果表明，影响等离子体速度分布的主要因素有等离子体温度、等离子体电离分数和汽化物质提供的动力源。由于初始喷射速度大，蒸发动力源的存在，纵向速度uz与横向速度ur不同。用该模型计算的等离子体速度与Sanz等人（1985 Plasma Phys.Control. Fusion 27 329）与传统型号相比。
A physical model is proposed to study the laser-induced plasma dynamics expansion during irradiation of material by a high-intensity nanosecond pulsed laser beam. Based on a consideration of the plasma ionization effect and local conservations of mass, momentum and energy, combined with the assumption that plasma can be viewed as a compressible ideal fluid and a high temperature–high pressure ideal gas, we developed a new dynamics expansion mechanism for plasma produced by pulsed laser radiation. A set of new plasma expansion dynamics equations based on our model are first deduced. Then, taking the example of the carbon target, using the finite difference method, the plasma flow dynamics into a vacuum, such as plasma spacial number density distribution, plasma number density and velocity evolvement in radial and axial directions, are studied in detail. The results show that there are some main factors affecting the velocity distribution of the plasma, including the temperature of the plasma, the ionization fraction of the plasma and the dynamic source provided by the vaporized material. The velocity uz in the longitudinal direction is different from ur in the transverse direction because of huge initial eject velocity and evaporated dynamic source. The velocities of the plasma calculated by this model are found to be in better agreement with the experimental results derived from the work of Sanz et al (1985 Plasma Phys. Control. Fusion 27 329) compared with the conventional model.