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本文中进行的所有实验都是在一个总能量为100J的实验装置上进行的。如图 1所示,超短脉冲激光(4ns,波长1053nm)以45°角照射铜箔产生的电磁脉冲采用B-dot天线进行测量。为有效地对比分析,用连接在带宽为8GHz的示波器(Agilent Infiniium DSO80804B/8GHz40gsa/)上的几个超小B-dot(EMP探头)对电磁脉冲进行定点测量。所有天线被放置在距离靶室中心3cm的6个不同方向,分别为45°, 67.5°, 75°, 90°, 105°和135°(所有这些角度都是以激光入射的零度方向作为参考给出的)。为了比较EMP特征,采用的是同一种靶,但支撑靶体的靶杆分别为导电型和绝缘型以观察回流电流对电磁辐射的影响。表 1中给出了打靶的发次编号与激光能量、EMP探头的对应关系。
表 1 The laser energy and types of targets
shot laser energy /J stalk 1 63.9 conductive 2 64.7 insulative 3 50.2 insulative 4 70.7 insulative 5 51.1 conductive 6 40.6 conductive 7 69.0 conductive 8 52.8 insulative 9 54.5 insulative
纳秒激光耦合金属靶辐射电磁脉冲的实验研究
Measurement of electromagnetic pulses generation from ns-laser coupling with metaltargets
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摘要: 为了研究电磁脉冲(EMP)强度和分布与激光参量、靶体材料、结构等之间的关系,采用靶室内部的超小B-dot天线对强激光打靶过程中产生的电磁脉冲进行了测量,分析了不同辐射方位的脉冲强度,同时探讨了靶体支撑杆为绝缘体和导体两种情况下的电磁辐射行为。结果表明,不同方向和不同靶杆测得的电磁脉冲明显不同,如在法线方向的电磁辐射达到20V,导电靶杆最大达到22V的辐射,说明强激光打靶诱导的EMP具有很强的极化方向,并且在导体靶杆情况下,能够产生更强的电磁辐射。该研究有助于揭示激光打靶产生的EMP在靶室内部的传输极化特性以及其强度与靶杆导电性的关系。Abstract: In order to study the relationships of the intensity and distribution of electromagnetic pulses (EMP) with laser parameters, target materials and configuration, the ultra-small B-dot antenna inside the target chamber was used to measure the electromagnetic pulses generated during the strong laser shooting metal copper targets. The pulse intensities in different radiation directions were analyzed. At the same time, electromagnetic radiation in the cases where the target support rod was an insulator and a conductor were discussed. The electromagnetic pulse shows a maximum value of 20V in the normal direction and 22V for the conductive rod, which indicates that EMP induced by strong laser targets has a strong polarized direction and can produce stronger electromagnetic radiation in the case of conductive target rods. The conclusion of this experiment is helpful for revealing the transmission polarization characteristics of EMP generated by laser target interaction in the target chamber and the relationship between its intensity and the conductivity of the target rod.
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Key words:
- laser physics /
- electromagnetic pulse /
- solid target /
- polarization
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表 1 The laser energy and types of targets
shot laser energy /J stalk 1 63.9 conductive 2 64.7 insulative 3 50.2 insulative 4 70.7 insulative 5 51.1 conductive 6 40.6 conductive 7 69.0 conductive 8 52.8 insulative 9 54.5 insulative -
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