When high-energy and high-power lasers interact with matter, a significant part of the incoming laser energy is transformed into transient electromagnetic pulses (EMPs) in the range of radiofrequencies and microwaves. These fields can reach high intensities and can potentially represent a significative danger for the electronic devices placed near the interaction point. Thus, the comprehension of the origin of these electromagnetic fields and of their distribution is of primary importance for the safe operation of high-power and high-energy laser facilities, but also for the possible use of these high fields in several promising applications. A recognized main source of EMPs is the target positive charging caused by the fast-electron emission due to laser–plasma interactions. The fast charging induces high neutralization currents from the conductive walls of the vacuum chamber through the target holder. However, other mechanisms related to the laser–target interaction are also capable of generating intense electromagnetic fields. Several possible sources of EMPs are discussed here and compared for high-energy and high-intensity laser–matter interactions, typical for inertial confinement fusion and laser–plasma acceleration. The possible effects on the electromagnetic field distribution within the experimental chamber, due to particle beams and plasma emitted from the target, are also described. This article is part of a discussion meeting issue ‘Prospects for high gain inertial fusion energy (part 2)’.

中文翻译：

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惯性约束聚变和激光等离子体加速实验中电磁脉冲的来源和时空分布

当高能和高功率激光与物质相互作用时，入射激光能量的很大一部分会转化为射频和微波范围内的瞬态电磁脉冲 (EMP)。这些场可以达到高强度，并且可能对放置在交互点附近的电子设备构成重大危险。因此，了解这些电磁场的起源及其分布对于高功率和高能激光设施的安全运行至关重要，而且对于这些高场在几个有前景的应用中的可能使用也是至关重要的。EMPs 的一个公认主要来源是由激光-等离子体相互作用引起的快速电子发射引起的目标正电荷。快速充电从真空室的导电壁通过靶架感应出高中和电流。然而，与激光-目标相互作用相关的其他机制也能够产生强烈的电磁场。这里讨论了几种可能的 EMP 来源，并比较了高能和高强度激光-物质相互作用，典型的惯性约束聚变和激光-等离子体加速。还描述了由于从目标发射的粒子束和等离子体对实验室内电磁场分布的可能影响。本文是“高增益惯性聚变能的前景（第 2 部分）”讨论会议问题的一部分。与激光-目标相互作用相关的其他机制也能够产生强烈的电磁场。这里讨论了几种可能的 EMP 来源，并比较了高能和高强度激光-物质相互作用，典型的惯性约束聚变和激光-等离子体加速。还描述了由于从目标发射的粒子束和等离子体对实验室内电磁场分布的可能影响。本文是“高增益惯性聚变能的前景（第 2 部分）”讨论会议问题的一部分。与激光-目标相互作用相关的其他机制也能够产生强烈的电磁场。这里讨论了几种可能的 EMP 来源，并比较了高能和高强度激光 - 物质相互作用，典型的惯性约束聚变和激光 - 等离子体加速。还描述了由于从目标发射的粒子束和等离子体对实验室内电磁场分布的可能影响。本文是“高增益惯性聚变能的前景（第 2 部分）”讨论会议问题的一部分。典型的惯性约束聚变和激光等离子体加速。还描述了由于从目标发射的粒子束和等离子体对实验室内电磁场分布的可能影响。本文是“高增益惯性聚变能的前景（第 2 部分）”讨论会议问题的一部分。典型的惯性约束聚变和激光等离子体加速。还描述了由于从目标发射的粒子束和等离子体对实验室内电磁场分布的可能影响。本文是“高增益惯性聚变能的前景（第 2 部分）”讨论会议问题的一部分。