Sources and space–time distribution of the electromagnetic pulses in experiments on inertial confinement fusion and laser–plasma acceleration

Abstract

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)’.

Preparations for a European R&D roadmap for an inertial fusion demo reactor

“…The European consortium has also undertaken studies of stable channel formation in fusion relevant plasmas [ 36 – 38 ], electromagnetic pulse generation and mitigation [ 39 ], UV fast electron generation and energy transport [ 40 ], magnetic fields [ 41 ], reactor materials under hostile radiation environments [ 23 ], among others, including the role of magnetic fields in guiding fast electrons.…”

Transient electromagnetic fields generated in experiments at the PHELIX laser facility

“…These experiments aim at studying various fields of physics, such as laser-driven particle acceleration [1], laboratory astrophysics [2] [3] [4] and iondriven fast ignition approach for inertial confinement fusion [5]. One of the consequences of the laser-target interaction is the generation of pulsed electromagnetic fields (EMPs) [6] [7]. The mechanisms that drive these EMPs can be different -depending on the interaction regime -and electromagnetic (e.m.) radiation with associated different features can be thus emitted at different intensities (up to several MV/m) and frequencies (from the MHz to the THz range) [6] [7].…”

“…One of the consequences of the laser-target interaction is the generation of pulsed electromagnetic fields (EMPs) [6] [7]. The mechanisms that drive these EMPs can be different -depending on the interaction regime -and electromagnetic (e.m.) radiation with associated different features can be thus emitted at different intensities (up to several MV/m) and frequencies (from the MHz to the THz range) [6] [7]. The most well-known EMP emission mechanism is related to the neutralization current that flows through the target holder due to the laser pulse depleting the solid target from electrons [8] [9] [10] [11] [12].…”

“…The amplitude of the electric field can reach the MV/m order and it represents one main hazard for electronic devices nearby, due to efficient e.m. coupling in this frequency rage. However, intense electric fields can also be generated by the charged particles that are emitted from the irradiated target [7] [13] [14] [15]: ion wakefields and charge accumulation on surrounding objects can lead to intense quasistatic fields that superimpose to the RF EMP signal. In Ref.…”

Prospects for high gain inertial fusion energy: an introduction to the second edition

“…Consoli et al . 's paper ‘Sources and space–time distribution of the electromagnetic pulses in experiments on inertial-confinement-fusion and laser–plasma acceleration’ [26] provides a succinct overview of experiments to quantify the scale of electromagnetic pulses in current-day experiments. This is needed when these devices are scaled up to those that will be required for full-scale tests of fast ignition.…”