真空环境下脉冲激光烧蚀等离子体羽流特性分析

Characteristics of plasma plume pulse laser ablation in vacuum

  • 摘要: 激光清除空间碎片利用的是高能脉冲激光烧蚀固体靶材的冲量耦合效应,对于空间碎片来说,激光辐照下的反冲冲量取决于碎片等离子体羽流的喷射过程,并且会随着激光辐照方向的变化而变化。因此,有必要研究空间碎片激光辐照下的等离子体羽流特性。针对等离子体羽流的流场超高速、瞬态、强自发光背景、小尺度的技术难点,采用纳秒级曝光、多幅照片精确拼接技术,采用高速相机和激光器同步时序控制技术,实现纳秒级时间分辨率、亚微米级空间分辨率的流场演化信息定量测量,实验获得典型碎片材料等离子体羽流演化特性,以及不同激光入射角度下的等离子体羽流演化过程,实验结果可揭示反喷冲量形成规律。

     

    Abstract: High power pulse laser ablation impulse effect can be used in the field of laser orbital debris removal. The recoil impulse of the space debris by laser ablation depends on the plasma plume expansion progress, and it will be changed by the change of laser ablation direction. Hence, it was necessary to study the characteristics of the plasma plume by laser ablation. Aim at the difficulties of ultra high speed, instantaneous condition, strong self luminescence and the small scale of the flow field, the technologies of ns exposure and precise stitching of multiple photos are adopted. Besides, the technology of controlling signal simultaneously with the high speed camera and laser power source was used. All these can achieve the ns scale time resolution and mm scale space resolution in the flow field quantitative measurement, which can be used to obtain the plasma plume evolution information. The plasma plume evolution characteristics of typical space debris material was obtained through experiments, also, the results of plasma plume expansion progress in different laser incident angle. The experimental results can reveal the change rule of the recoil impulse by pulsed laser ablation.

     

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