Spectral and spatial characterisation of laser-driven positron beams

Sarri, Gianluca; Warwick, J.; Schumaker, W.; Põder, Kristjan; Cole, J. M.; Doria, D.; Dzelzainis, T.; Krushelnick, K.; Kuschel, S.; Mangles, Stuart; Najmudin, Z.; Romagnani, L.; Samarin, G. M.; Symes, D. R.; Thomas, Alexander; Yeung, M.; Zepf, M.

doi:10.1088/0741-3335/59/1/014015

Cited by 18 publications

(15 citation statements)

References 33 publications

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“…We disagree with this statement. The applicability of LWFA-driven positrons to advanced accelerator concepts is currently subject of investigation, and our recent work [3,4,6], together with that of independent groups [7,8], confirms that there is significant potential in this area. We have also confirmed that such positron beams can be used for some specific studies in laboratory astrophysics, and we have already experimentally measured plasmalike behavior of LWFAdriven electron-positron beams [9][10][11][12].…”

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confidence: 62%

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et al. 2020

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Sarri et al. Reply: The Comment [1] reports on independent numerical simulations of the experimental results in Ref. [2]. Positron yields and spectra similar to those in Ref. [2] are numerically obtained, but with a larger divergence. A larger positron source size at the rear of the converter is hence inferred, resulting in a smaller positron density. Since the publication of the Letter, comprehensive Monte Carlo simulations of the characteristics of such positron beams have already been published by members of our collaboration [3]. The simulations discussed in the Comment are only a specific subset of this more extensive work, and largely agree with it on the divergence.

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confidence: 62%

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“…An alternative method for the generation of neutral electron-positron plasmas has been identified in exploiting the quantum cascade initiated by a laser-driven electron beam propagating through a solid target. Even though this method suffers from the difficulty of generating cold populations and confining them, promising results have been obtained in different configurations [11,12,13,14,15,16,17], with, to-date, the first experimental demonstration of a neutral electron-positron beam able to show collective behaviour [14,17]. The details of the laser-driven generation of neutral electron-positron beams (EPBs) can be found elsewhere [13,14,15,16]; in this paper, we will instead focus our attention on some of the main experimental issues involved in detecting the dynamics of these objects, when they propagate through a background electron-ion plasma.…”

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confidence: 99%

General features of experiments on the dynamics of laser-driven electron–positron beams

Warwick

Alejo

Dzelzainis

et al. 2018

Nuclear Instruments and Methods in Physics Research Section A:

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The experimental study of the dynamics of neutral electron-positron beams is an emerging area of research, enabled by the recent results on the generation of this exotic state of matter in the laboratory. Electron-positron beams and plasmas are believed to play a major role in the dynamics of extreme astrophysical objects such as supermassive black holes and pulsars. For instance, they are believed to be the main constituents of a large number of astrophysical jets, and they have been proposed to significantly contribute to the emission of gamma-ray bursts and their afterglow. However, despite extensive numerical modelling and indirect astrophysical observations, a detailed experimental characterisation of the dynamics of these objects is still at its infancy. Here, we will report on some of the general features of experiments studying the dynamics of electron-positron beams in a fully laserdriven setup.

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“…The rear side of the gas-cell was covered with a LANEX scintillator screen, in order to provide information about the spatial distribution of the EPB with and without the second gas-cell. During free propagation, the EPB presents a smooth spatial profile, well approximated by a super-gaussian [37]. Finally, a magnetic spectrometer allowed separating and measuring the spectrum of the electrons and positrons in the beam on each laser shot.…”

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Experimental Observation of a Current-Driven Instability in a Neutral Electron-Positron Beam

et al. 2017

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We report on the first experimental observation of a current-driven instability developing in a quasineutral matter-antimatter beam. Strong magnetic fields (amp;gt;= 1 T) are measured, via means of a proton radiography technique, after the propagation of a neutral electron-positron beam through a background electron-ion plasma. The experimentally determined equipartition parameter of epsilon(B) approximate to 10(-3) is typical of values inferred from models of astrophysical gamma-ray bursts, in which the relativistic flows are also expected to be pair dominated. The data, supported by particle-in-cell simulations and simple analytical estimates, indicate that these magnetic fields persist in the background plasma for thousands of inverse plasma frequencies. The existence of such long-lived magnetic fields can be related to analog astrophysical systems, such as those prevalent in lepton-dominated jets.

Funding Agencies|EPSRC [EP/N022696/1, EP/N027175/1, EP/L013975/1, EP/N002644/1, EP/P010059/1]; DOE [DE-NA0002372]; ARO [W911NF-16-1-0044]

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Spectral and spatial characterisation of laser-driven positron beams

Cited by 18 publications

References 33 publications

Sarri et al. Reply:

Sarri et al. Reply:

General features of experiments on the dynamics of laser-driven electron–positron beams

Experimental Observation of a Current-Driven Instability in a Neutral Electron-Positron Beam

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