超高速激光纹影技术测量脉冲功率驱动的磁重联现象

Measurement of magnetic reconnection driven by pulse power using ultra high speed laser schlieren technology

用超高速激光纹影技术测量了Z箍缩等离子体磁重联现象。实验采用超高速光电分幅相机,配合激光纹影技术,测量了XP-1装置上两根金属丝产生的等离子体分布,论证了超高速激光纹影技术研究Z箍缩磁重联现象的可行性。双钨丝实验结果表明,电流加载约10ns后金属丝已有明显膨胀,线性拟合得到平均膨胀速度约8km/s,金属丝内外两侧出现了规则的极有可能是垂直磁场的电热不稳定性扰动,并沿角向高度关联。铝丝负载的实验结果表明,早期的不稳定性波长为0.4mm,电流峰值之后金属丝初始位置仍有大量等离子体,后期的不稳定性波长约1.5mm。这些现象揭示了不稳定性发展的一个主要特征:短波模式受抑制,长波模式将占主导。

Magnetic reconnection in Z-pinch plasma have been measured using ultra high speed laser schlieren technology.Through measurement of plasma distribution of two wires on the XP-1,it is demonstrated that study of magnetic reconnection in Z-pinch plasma is feasible through ultra high speed optic electronic framing camera and schlieren technology.The results of two tungsten wire experiment indicate that the wires start expanding 10 ns after current loading at approximately 8km/s,and in inner and outer sides of the wires,there are highly possible electrothermal instability vertical to magnetic field.The results of two tungsten wire experiment indicate that the early instability wavelength is 0.4mm and becomes 1.5mm at later stage,there is still plenty of plasma in the initial position after current peak.These phenomena reveal a principal characteristic of instability:as it develops,the long wave mode will be dominant and the short wave mode will be restrained.