Belony Paul A, Kim Yong W
Department of Physics, Lehigh University, Bethlehem, Pennsylvania 18015, USA.
Rev Sci Instrum. 2010 Oct;81(10):10E512. doi: 10.1063/1.3475790.
X-pinch plasmas have been actively studied in the recent years. Numerical simulation of the ramp-up of metallic vapor emissions from wire specimens shows that under impulsive Ohmic heating the wire core invariably reaches a supercritical state before explosion. The heating rate depends sensitively on the local wire resistance, leading to highly variable vapor emission flux along the wire. To examine the vapor emission process, we have visualized nickel wire explosions by means of shock formation in air. In a single explosion as captured by shadowgraphy, there usually appear several shocks with spherical or cylindrical wave front originating from different parts of the wire. Growth of various shock fronts in time is well characterized by a power-law scaling in one form or another. Continuum emission spectra are obtained and calibrated to measure temperature near the explosion threshold. Shock front structures and vapor plume temperature are examined.
近年来，X 箍缩等离子体一直是研究的热点。对金属丝样本中金属蒸汽发射增强过程的数值模拟表明，在脉冲欧姆加热下，金属丝芯在爆炸前总会达到超临界状态。加热速率敏感地取决于局部金属丝电阻，导致沿金属丝的蒸汽发射通量高度可变。为了研究蒸汽发射过程，我们通过在空气中形成激波的方式对镍丝爆炸进行了可视化观察。在阴影照相术捕捉到的单次爆炸中，通常会出现几个具有球面或柱面波前的激波，它们源自金属丝的不同部位。各种激波前沿随时间的增长很好地符合某种幂律标度关系。获取并校准了连续发射光谱，以测量爆炸阈值附近的温度。研究了激波前沿结构和蒸汽羽流温度。
