激光诱导铝合金E414d等离子体电子温度的空间分布

Spatial distribution of electron temperature of laser-induced aluminum alloy E414d plasma

采用调Q Nd:YAG脉冲激光诱导铝合金E414d,研究了等离子体的谱线强度、电子温度和电子密度。建立Al(Ⅰ)256.80nm、Al(Ⅰ)308.21nm和Al(Ⅰ)396.15nm的波耳兹曼平面,实验发现距靶面高度1.5mm处等离子体的电子温度最高。罗仑兹函数拟合Mg(Ⅰ)285.21nm得到等离子体的电子密度是1.9×1018 cm-3,远大于局域热力学平衡所需的电子密度值9.8×1015 cm-3,证明实验得到的等离子体满足局部热力学平衡。

Parameters of the laser-induced aluminum alloy E414d plasma are studied.The Local Thermodynamic Equilibrium（LTE） is proved valid for the electron number density（1.9×1018 cm-3）,inferred from the Lorentz fit of Mg（Ⅰ） 285.21 nm,is lager than the lower limit（9.8×1015 cm-3） for LTE exists.The electron temperatures at different height are determined using the Blotzmann plot method with Al（Ⅰ） 256.80 nm,Al（Ⅰ） 308.21 nm and Al（Ⅰ） 396.15 nm.The electron temperature is maximum at the distance of 1.5 mm above the target surface and it decreases both at the plasma edge and close to the target surface.The physical explanations for this spatial distribution are presented.