爆磁准等熵加载下真空管道压缩与通光特性

Compression and Light Transmission Characteristics of Vacuum Tube under Magnetic Flux Compression Generator Driven Quasi-Isentropic Loading

柱面爆磁准等熵加载技术可实现低密度材料的超高压力加载。为获取压缩后样品的光学特性,新提出了一种利用金属真空管道作为光传输通道的真空导光探针结构,以避免加载压力对光测路径的影响。为评估爆磁准等熵加载实验中真空导光探针光学诊断通道的闭合性质,对高密度金属真空管道在柱面内爆准等熵加载下的压缩特性和通光特性进行了分析和实验测试。采用单级爆磁加载装置CJ-100开展了水的爆磁准等熵压缩实验,通过对比分析钽管内壁速度测量结果和理论计算结果,发现对于外径3 mm、内径2 mm的真空钽管,当压力约为485 GPa时,钽管内径被压缩至1.28 mm,钽管空腔内的光信号传输以及钽管内光纤和光纤探头的传输通道一直保持畅通,钽管内径被压缩至1.28 mm之后,光信号仍然存在约50 ns。这说明采用由钽等高密度金属材料制成的真空导光管道开展柱面内爆加载下样品的光学特性测量是可行的,为爆磁准等熵加载实验中样品高压光学特性测量提供了新的技术途径。

Cylindrical quasi-isentropic compression driven by explosive magnetic flux compression generator(MFCG)enables ultra-high pressure loading of low-density materials.To obtain the optical properties of the compressed sample,a new vacuum light-guide probe structure using metal vacuum tube as the optical transmission channel is proposed to avoid the influence of loading pressure on the optical measurement path.In order to evaluate whether the optical diagnostic channel of the vacuum light-guide probe is closed in the MFCG quasi-isentropic loading experiment,the compression characteristics and light transmission characteristics of the cavity of the high-density metal vacuum tube under cylindrical implosion quasi-isentropic loading were analyzed and experimentally tested.In the experiment of compressing water conducted on the single-stage MFCG device CJS-100,through the comparative analysis of the measurement results of the inner shell velocity of the Ta tube and the theoretical calculation results,the inner diameter of the Ta tube with an outer diameter of 3 mm and an inner diameter of 2 mm is compressed to 1.28 mm when the water is quasi-isentropic loaded to about 485 GPa.During this time,the optical signal transmission channels of the Ta tube cavity and the optical fiber and fiber probe inside the Ta tube remain open.The optical signal remains present for about 50 ns after the inner diameter of the Ta tube is compressed to 1.28 mm.The results show that the measurement of optical characteristics of cylindrical implosion loading samples is feasible by using vacuum light-guide tube made of high-density metal materials such as Ta,which provides a new technical way for the measurement of optical properties of high-pressure samples in MFCG driven quasi-isentropic loading experiments.