Analysis of electromagnetic pulse (EMP) measurements in the National Ignition Facility's target bay and chamber

Brown, Charles G.; Clancy, T. J.; Eder, D. C.; Throop, A.L.

doi:10.1051/epjconf/20135908012

Cited by 17 publications

(12 citation statements)

References 6 publications

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“…This phenomenon has been known since the seventies and has been investigated at numerous facilities. [2][3][4][5][6][7][8][9][10] Laser-driven EMP emission, spanning a broad frequency range from MHz to THz, can seriously disrupt electronic equipment used for facility operation or scientific measurement. On the other hand, if properly controlled, these emissions may lead to new experimental applications.…”

Section: Introductionmentioning

confidence: 99%

Electromagnetic pulse emission from target holders during short-pulse laser interactions

et al. 2020

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For the first time, a global model of electromagnetic pulse (EMP) emission connects charge separation in the laser target to quantitative measurements of the electromagnetic field. We present a frequency-domain dipole antenna model which predicts the quantity of charge accumulated in a laser target as well as the EMP amplitude and frequency. The model is validated against measurements from several high-intensity laser facilities, providing insight into target physics and informing the design of next-generation ultra-intense laser facilities. EMP amplitude is proportional to the total charge accumulated on the target, but we demonstrate that it is not directly affected by target charging time (and therefore the laser pulse duration) provided the charging time is shorter than the antenna characteristic time. We propose two independent methods for estimating the charging time based on the laser pulse duration. We also investigate the impact of target holder geometry on EMPs using cylindrical, conical and helical holders. Published as: Minenna et al., Phys. Plasmas, 27, 063102 (2020), https://doi.

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Section: Introductionmentioning

confidence: 99%

Electromagnetic pulse emission from target holders during short-pulse laser interactions

et al. 2020

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“…With the advent of petawatt lasers and MJ laser facilities the issue of EMP became of considerable practical interest, because such pulses strongly interfere with the electronics used to collect data and manipulate targets and hence pose a serious threat to safe and reliable execution of experiments. Therefore a dedicated effort was made to study the EMP effect at facilities such as Vulcan, Titan, Omega, NIF, LMJ and other (Mead et al, 2004;Raimbourg, 2004;Stoeckl et al, 2006;Remo et al, 2007;Brown et al, 2008;Bourgade et al, 2008;Eder et al, 2009;Brown et al, 2010;Eder et al, 2010;Chen et al, 2011;Bateman & Mead, 2012;Brown et al, 2012;Brown et al, 2013;). Pulses of 100's ns duration and electric fields of 100's kV/m strength were recorded.…”

Section: Introductionmentioning

confidence: 99%

Strong electromagnetic pulses generated in high-intensity short-pulse laser interactions with thin foil targets

et al. 2017

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Measurements are reported of the target neutralization current, the target charge, and the tangential component of the magnetic field generated as a result of laser-target interaction by pulses with the energy in the range of 45 mJ to 92 mJ on target and the pulse duration from 39 fs to 1000 fs. The experiment was performed at the Eclipse facility in CELIA, Bordeaux. The aim of the experiment was to extend investigations performed for the thick (mm scale) targets to the case of thin (µm thickness) targets in a way that would allow for a straightforward comparison of the results. We found that thin foil targets tend to generate 20%-50% higher neutralization current and the target charge than the thick targets. The measurement of the tangential component of the magnetic field had shown that the initial spike is dominated by the 1 ns pulse consistent with the 1 ns pulse of the neutralization current, but there are some differences between targets of different type on sub-ns scale, which is an effect going beyond a simple picture of the target acting as an antenna. The sub-ns structure appears to be reproducible to surprising degree. We found that there is in general a linear correlation between the maximum value of the magnetic field and the maximum neutralization current, which supports the target-antenna picture, except for pulses 100's of fs long.Keywords: electromagnetic pulses, neutralization current, electric polarization of the target, */ Corresponding author: P. Rączka, Division of Laser Plasma, Institute of Plasma Physics and Laser Microfusion, ul. Hery 23, 01-497 Warsaw, Poland; tel. +48 22 6381005 ext. 20. 1.INTRODUCTIONOne of the characteristic effects observed in the experiments performed with the use of highenergy, high-intensity lasers is the appearance of strong electromagnetic pulses (EMP) with frequencies ranging from tens of MHz to multi-GHz. First accounts of the rf to microwave emission resulting from the laser-target interactions were published already in the seventies (Pearlman & Dahlbacka, 1978). With the advent of petawatt lasers and MJ laser facilities the issue of EMP became of considerable practical interest, because such pulses strongly interfere with the electronics used to collect data and manipulate targets and hence pose a serious threat to safe and reliable execution of experiments. Therefore a dedicated effort was made to study the EMP effect at facilities such as Vulcan, Titan, Omega, NIF, LMJ and other (Mead et al., 2004;Raimbourg, 2004;Stoeckl et al., 2006;Remo et al., 2007;Brown et al., 2008; Bourgade et al., 2008; Eder et al., 2009; Brown et al., 2010; Eder et al., 2010;Chen et al., 2011;Bateman & Mead, 2012;Brown et al., 2012;Brown et al., 2013;). Pulses of 100's ns duration and electric fields of 100's kV/m strength were recorded. Various EMP generation mechanisms had been considered at this stage, including the charge separation effects in laser plasmas and low-frequency oscillations of the expanding plasmas (Pearlman & Dahlbacka, 1978), the electron currents wit...

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“…Reducing EMP is therefore of potential benefit to experiments at major laser facilities such as the National Ignition Facility. 12,13 Due to these compelling advantages, levitated targets have a number of exciting potential applications. For example, as sources for high resolution X-ray and particle imaging due to their micron-scale size and high energy X-ray emission, low debris, expected high (sub-ps) time-resolution, and low EMP.…”

Section: Introductionmentioning

confidence: 99%

An in-vacuo optical levitation trap for high-intensity laser interaction experiments with isolated microtargets

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Donnelly

Giltrap

et al. 2015

Review of Scientific Instruments

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We report on the design, construction, and characterisation of a new class of in-vacuo optical levitation trap optimised for use in high-intensity, high-energy laser interaction experiments. The system uses a focused, vertically propagating continuous wave laser beam to capture and manipulate micro-targets by photon momentum transfer at much longer working distances than commonly used by optical tweezer systems. A high speed (10 kHz) optical imaging and signal acquisition system was implemented for tracking the levitated droplets position and dynamic behaviour under atmospheric and vacuum conditions, with ±5 μm spatial resolution. Optical trapping of 10 ± 4 μm oil droplets in vacuum was demonstrated, over timescales of >1 h at extended distances of ∼40 mm from the final focusing optic. The stability of the levitated droplet was such that it would stay in alignment with a ∼7 μm irradiating beam focal spot for up to 5 min without the need for re-adjustment. The performance of the trap was assessed in a series of high-intensity (10(17) W cm(-2)) laser experiments that measured the X-ray source size and inferred free-electron temperature of a single isolated droplet target, along with a measurement of the emitted radio-frequency pulse. These initial tests demonstrated the use of optically levitated microdroplets as a robust target platform for further high-intensity laser interaction and point source studies.

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Analysis of electromagnetic pulse (EMP) measurements in the National Ignition Facility's target bay and chamber

Cited by 17 publications

References 6 publications

Electromagnetic pulse emission from target holders during short-pulse laser interactions

Electromagnetic pulse emission from target holders during short-pulse laser interactions

Strong electromagnetic pulses generated in high-intensity short-pulse laser interactions with thin foil targets

An in-vacuo optical levitation trap for high-intensity laser interaction experiments with isolated microtargets

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