光学学报, 2018, 38 (8): 0830001, 网络出版: 2018-09-06
半球形空腔约束等离子体的时空演变特性研究 下载: 892次
Temporal and Spatial Evolution Characteristics of Plasma Confined by Hemispherical Cavity
光谱学 激光诱导击穿光谱 等离子体 半球形空腔 时空演变 spectroscopy laser-induced breakdown spectroscopy plasma hemispherical cavity temporal and spatial evolution
摘要
为研究半球形空腔对等离子体辐射的增强作用,利用不同直径的半球形空腔对激光烧蚀合金钢产生的等离子体进行约束,结果发现,半球形空腔对等离子体辐射的最佳增强倍数随着半球形空腔直径的增大呈现先增大后减小再增大最后减小的规律,且最佳增强倍数对应的延迟时间与半球形空腔直径存在线性关系。分析结果表明:最佳的半球形空腔直径为10 mm,延迟时间为10 μs时,采用该直径的半球形空腔对等离子体辐射具有最优的增强效果。对无约束和半球形空腔约束下的等离子体辐射光谱进行了空间分辨测量,结果发现:在无约束情况下,随着膨胀扩张,等离子体演变为尺寸较大且强度较低的辐射源;在半球形空腔约束情况下,等离子体尺寸较小,但强度较高。研究结果表明,等离子体的辐射增强是半球形空腔对等离子体的三维空间压缩效应引起的,且增强效果受半球形空腔直径的影响。
Abstract
In order to study the enhancement effect of hemispherical cavity on plasma emission, we use hemispherical cavity with different diameters to confine the plasma generated by laser ablation alloy steel. It is found that the optimum enhancement factor of the hemispherical cavity on the plasma emission increases first, then decreases, then increases and finally decreases with the increase of the hemispherical cavity diameter. There is a linear relationship between the delay time corresponding to the best enhancement factor and the hemispherical cavity diameter. The results have shown that the hemispherical cavity has the best enhancement effect on the plasma emission when the diameter is 10 mm and the corresponding delay time is 10 μs. Spatial resolution measurement of the plasma emission spectra with and without hemispherical cavity are measured. It is found that the plasma without confinement evolved into an emission source with larger size and less intensity as a result of expansion. Whereas the plasma has a smaller size but higher intensity with hemispherical cavity confinement. It is demonstrated that the enhancement of the plasma emission is caused by the three-dimensional compression effect of the hemispherical cavity on the plasma, and the enhancement effect is affected by the diameter of the hemispherical cavity.
李小龙, 王静鸽, 张利平, 李新忠. 半球形空腔约束等离子体的时空演变特性研究[J]. 光学学报, 2018, 38(8): 0830001. Xiaolong Li, Jingge Wang, Liping Zhang, Xinzhong Li. Temporal and Spatial Evolution Characteristics of Plasma Confined by Hemispherical Cavity[J]. Acta Optica Sinica, 2018, 38(8): 0830001.