Nelissen Kwinten, Liszi Máté, Marco Massimo De, Ospina Valeria, Drotár István, Gatti Giancarlo, Kamperidis Christos, Volpe Luca
ELI-ALPS, ELI-HU Non-Profit Ltd., Dugonics tér 13, Szeged, 6720, Hungary.
Laser-Plasma Chair at the University of Salamanca, Salamanca, Spain.
Sci Rep. 2020 Feb 20;10(1):3108. doi: 10.1038/s41598-020-59882-8.
Recent advances on laser technology have enabled the generation of ultrashort (fs) high power (PW) laser systems. For such large scale laser facilities there is an imperative demand for high repetition rate operation in symbiosis with beamlines or end-stations. In such extreme conditions the generation of electromagnetic pulses (EMP) during high intense laser target interaction experiments can tip the scale for the good outcome of the campaign. The EMP effects are several including interference with diagnostic devices and actuators as well as damage of electrical components. The EMP issue is quite known in the picosecond (ps) pulse laser experiments but no systematic study on EMP issues at multi-Joule fs-class lasers has been conducted thus far. In this paper we report the first experimental campaign for EMP-measurements performed at the 200 TW laser system (VEGA 2) at CLPU laser center. EMP pulse energy has been measured as a function of the laser intensity and energy together with other relevant quantities such as (i) the charge of the laser-driven protons and their maximum energy, as well as (ii) the X-ray K emission coming from electron interaction inside the target. Analysis of experimental results demonstrate (and confirm) a direct correlation between the measured EMP pulse energy and the laser parameters such as laser intensity and laser energy in the ultrashort pulse duration regime. Numerical FEM (Finite Element Method) simulations of the EMP generated by the target holder system have been performed and the simulations results are shown to be in good agreement with the experimental ones.
激光技术的最新进展已能够产生超短（飞秒）高功率（拍瓦）激光系统。对于如此大规模的激光设施，迫切需要与光束线或终端站共生运行的高重复频率。在这种极端条件下，高强度激光与靶相互作用实验期间产生的电磁脉冲（EMP）可能会影响实验的良好结果。EMP的影响有多种，包括干扰诊断设备和执行器以及损坏电气元件。EMP问题在皮秒（ps）脉冲激光实验中是广为人知的，但迄今为止尚未对多焦耳飞秒级激光的EMP问题进行系统研究。在本文中，我们报告了在CLPU激光中心的200太瓦激光系统（VEGA 2）上进行的首次EMP测量实验。测量了EMP脉冲能量与激光强度、能量以及其他相关量的函数关系，这些相关量包括：（i）激光驱动质子的电荷量及其最大能量，以及（ii）靶内电子相互作用产生的X射线K发射。实验结果分析表明（并证实），在超短脉冲持续时间范围内，测量的EMP脉冲能量与激光参数（如激光强度和激光能量）之间存在直接相关性。已经对靶架系统产生的EMP进行了数值有限元方法（FEM）模拟，模拟结果与实验结果吻合良好。
