EMP control and characterization on high-power laser systems

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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“…20 Note that this experimental arrangement is similar to Ref. 27, where different holder designs were also investigated.…”

Section: Experimental Set-upmentioning

confidence: 95%

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

et al. 2020

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“…By designing and controlling the interaction geometry to reduce [372] and mitigate [373] EMP generation, many general techniques [374] appropriate for 'single-shot' operation [375] can be delivered at high repetition rates ( 10 Hz) with suitable retuning/redesign and the replacement of the detector element or by transporting the signal to a more benign environment [376] before digitization (see Figure 41). Scintillators, phosphors and transducers capable of kHz-GHz rates can be readily coupled to gated or rep-rated high-dynamic-range detectors.…”

Section: Plasma Diagnosticsmentioning

confidence: 99%

Petawatt and exawatt class lasers worldwide

Danson

Haefner

Bromage

et al. 2019

High Pow Laser Sci Eng

781

406

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In the 2015 review paper ‘Petawatt Class Lasers Worldwide’ a comprehensive overview of the current status of high-power facilities of ${>}200~\text{TW}$ was presented. This was largely based on facility specifications, with some description of their uses, for instance in fundamental ultra-high-intensity interactions, secondary source generation, and inertial confinement fusion (ICF). With the 2018 Nobel Prize in Physics being awarded to Professors Donna Strickland and Gerard Mourou for the development of the technique of chirped pulse amplification (CPA), which made these lasers possible, we celebrate by providing a comprehensive update of the current status of ultra-high-power lasers and demonstrate how the technology has developed. We are now in the era of multi-petawatt facilities coming online, with 100 PW lasers being proposed and even under construction. In addition to this there is a pull towards development of industrial and multi-disciplinary applications, which demands much higher repetition rates, delivering high-average powers with higher efficiencies and the use of alternative wavelengths: mid-IR facilities. So apart from a comprehensive update of the current global status, we want to look at what technologies are to be deployed to get to these new regimes, and some of the critical issues facing their development.

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“…Capacitor coil magnetic fields of 1-1000 T have been reported at different laser facilities using a range of diagnostics, although harsh laser-plasma conditions make it difficult to reliably estimate the magnetic field inside the coil loop [1-3, 8, 16-19] . High-frequency B-dot probes can measure the full time evolution of a capacitor coil magnetic field, but are highly sensitive to electromagnetic pulse noise [20,21] and must be positioned several centimetres from the target to avoid radiation damage. This introduces significant errors in the signal analysis because the magnetic field geometry must be simulated and extrapolated over a long distance.…”

Section: Introductionmentioning

confidence: 99%

Proton deflectometry of a capacitor coil target along two axes

Bradford

Read

Ehret

et al. 2020

High Pow Laser Sci Eng

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A developing application of laser-driven currents is the generation of magnetic fields of picosecond–nanosecond duration with magnitudes exceeding $B=10~\text{T}$ . Single-loop and helical coil targets can direct laser-driven discharge currents along wires to generate spatially uniform, quasi-static magnetic fields on the millimetre scale. Here, we present proton deflectometry across two axes of a single-loop coil ranging from 1 to 2 mm in diameter. Comparison with proton tracking simulations shows that measured magnetic fields are the result of kiloampere currents in the coil and electric charges distributed around the coil target. Using this dual-axis platform for proton deflectometry, robust measurements can be made of the evolution of magnetic fields in a capacitor coil target.

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EMP control and characterization on high-power laser systems

Cited by 51 publications

References 22 publications

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

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

Petawatt and exawatt class lasers worldwide

Proton deflectometry of a capacitor coil target along two axes

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