All-optical beamlet train generation

An electron injector concept that uses a single injection laser pulse colliding with a pump laser pulse in a plasma is analyzed. The pump pulse generates a large amplitude laser wakefield (plasma wave). The counterpropagating injection pulse collides with the pump laser pulse to generate a beat wave with a slow phase velocity. The ponderomotive force of the slow beat wave is responsible for injecting plasma electrons into the wakefield near the back of the pump pulse. Test particle simulations indicate that significant amounts of charge can be trapped and accelerated (∼ 10 pC).For higher charge, beam loading limits the validity of the simulations. The accelerated bunches are ultrashort (∼ 1 fs) with good beam quality (relative energy spread of a few percent at a mean energy of ∼ 10 MeV and a normalized rms emittance on the order 0.4 mm.mrad). The effects of interaction angle and polarization are also explored, e.g., efficient trapping can occur for near-collinear geometries. Beat wave injection using a single injection pulse has the advantages of simplicity, ease of experimental implementation, and requires modest laser intensity I 8.8 × 10 17 W/cm 2 .

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“…The details of trapping using orthogonal polarizations are presently being explored using particle-in-cell simulations [23].…”

Section: Orthogonal Polarizationmentioning

confidence: 99%

Beat wave injection of electrons into plasma waves using two interfering laser pulses

et al. 2004

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“…For orthogonal polarization, trapping can occur, but for higher laser intensities in which nonlinear effects (not included in the test particle simulation model) become important. The details of trapping using orthogonal polarizations are presently being explored using particle-in-cell simulations [64].…”

Section: Orthogonal Polarizationmentioning

confidence: 99%

Controlled Electron Injection into Plasma Accelerators and SpaceCharge Estimates

Fubiani

2005

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Doctor Wim P. Leemans, ChairPlasma based accelerators are capable of producing electron sources which are ultra-compact (a few microns) and high energies (up to hundreds of MeVs) in much shorter distances than conventional accelerators. This is due to the large longitudinal electric field that can be excited without the limitation of breakdown as in RF structures. The characteristic scalelength of the accelerating field is the plasma wavelength and for typical densities ranging from 10 18 − 10 19 cm −3 , the accelerating fields and scalelength can hence be on the order of 10 − 100 GV/m and 10 − 40 µm, respectively.The production of quasi monoenergetic beams was recently obtained in a regime relying on self-trapping of background plasma electrons, using a single laser pulse for wakefield generation. In this dissertation, we study the controlled injection via the beating of two lasers (the pump laser pulse creating the plasma wave and a second beam being propagated in opposite direction) which induce a localized injection of background plasma electrons. The aim of this dissertation is to describe in detail the physics of optical injection using two lasers, the characteristics of the electron beams produced (the micrometer scale plasma wavelength can result in femtosecond and i ii Abstract even attosecond bunches) as well as a concise estimate of the effects of space charge on the dynamics of an ultra-dense electron bunch with a large energy spread. AcknowledgementsThere are many people that I wish to thank for valuable help they gave me during the course of my PhD. It was overall a great experience for me, I learned a lot in many areas and this work confirmed my deep passion for science in general.My great thanks to my adviser Wim Leemans. He gave me such a great opportunity by inviting me to come to l'OASIS group as a PhD student. He was always present for both the good and doubtful times when the results were not

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