Uniformity of cylindrical imploding underwater shockwaves at very small radii
Uniformity of cylindrical imploding underwater shockwaves at very small radii
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DOI：
10.1063/1.5005174
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发表时间：
2017-11
影响因子：
4
通讯作者：
D. Yanuka;A. Rososhek;S. Bland;Y. Krasik
中科院分区：
文献类型：
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作者：
D. Yanuka;A. Rososhek;S. Bland;Y. Krasik
我们比较了收敛冲击波产生的水下，圆柱形阵列的铜线爆炸的多个千安培的电流脉冲纳秒和微秒尺度。在这两种情况下，用于实验的脉冲功率装置具有相同的存储能量（10500 J），并且调整金属丝质量以优化能量传递到冲击波。冲击波阵面的激光背光分幅图像达到了30 μm的半径。结果发现，即使在初始方位不对称的情况下，冲击波的自我修复在其运动的最后阶段，导致一个高度一致的内爆。在这些和以前的实验中，当冲击波接近轴时，在条纹和框架图像中观察到干涉条纹。我们已经能够精确地模拟条纹的起源，这是由于激光束的传播衍射了均匀会聚的冲击波阵面。冲击波的动力学特性及其在小半径处的均匀性表明，
We compare the convergent shockwaves generated from underwater, cylindrical arrays of copper wire exploded by multiple kilo-ampere current pulses on nanosecond and microsecond scales. In both cases, the pulsed power devices used for the experiments had the same stored energy (∼500 J) and the wire mass was adjusted to optimize energy transfer to the shockwave. Laser backlit framing images of the shock front were achieved down to the radius of 30 μm. It was found that even in the case of initial azimuthal non-symmetry, the shock wave self-repairs in the final stages of its motion, leading to a highly uniform implosion. In both these and previous experiments, interference fringes have been observed in streak and framing images as the shockwave approached the axis. We have been able to accurately model the origin of the fringes, which is due to the propagation of the laser beam diffracting off the uniform converging shock front. The dynamics of the shockwave and its uniformity at small radii indicate that eve...