Laser wakefield compression and acceleration of externally injected electron bunches in guiding structures

AbstractFor the considered scheme of the external electron bunch injection in front of a laser pulse, the influence of the nonlinear driving laser pulse dynamics and electron bunch self-action to the processes of electron bunch compression and acceleration in the laser wakefield is analyzed. Self-consistent modelling results confirm that the nonlinear laser pulse dynamics limits the bunch compression due to variations of the phase velocity of the wake. A growth of the injected bunch charge leads to some extent to an increase of the trapped and accelerated bunch charge and to decrease of the trapped bunch radius and emittance due to increased self-focusing bunch. The three-dimensional theoretical model is elaborated and used to describe the propagation of laser pulses in dielectric capillary waveguides under imperfect coupling and focusing conditions with broken cylindrical symmetry. The role of cone entrances to the cylindrical part of a capillary is analyzed, and it is demonstrated that matching cones can considerably increase the transmission of laser pulses through the capillary, but cannot mitigate the requirements on the precision of the laser pulse focusing into a capillary. In order to avoid a speckle structure and strong transverse gradients of the fields, which can prevent the process of regular electron bunch acceleration, one has to ensure a small laser angle of incidence into the capillary not exceeding 1 mrad.

Download Full-text

Electron bunch injection at an angle into a laser wakefield

Laser and Particle Beams ◽

10.1017/s0263034609000093 ◽

2009 ◽

Vol 27 (1) ◽

pp. 69-77 ◽

Cited By ~ 10

Author(s):

M.J.H. Luttikhof ◽

A.G. Khachatryan ◽

F.A. van Goor ◽

K.-J. Boller ◽

P. Mora

Keyword(s):

Laser Pulse ◽

Electron Bunch ◽

Extensive Study ◽

Energy Spread ◽

Pulse Dynamics ◽

Electron Bunches ◽

Vacuum Plasma ◽

Laser Wakefield ◽

External Injection ◽

Wakefield Accelerator

AbstractExternal injection of electron bunches longer than the plasma wavelength in a laser wakefield accelerator can lead to the generation of femtosecond ultra relativistic bunches with a couple of percent energy spread. Extensive study has been done on external electron bunch (e.g., one generated by a photo-cathode RF linac) injection in a laser wakefield for different configurations.In this paper, we investigate a new way of external injection where the electron bunch is injected at a small angle into the wakefield. This way one can avoid the ponderomotive scattering as well as the vacuum-plasma transition region, which tend to destroy the injected bunch. In our simulations, the effect of the laser pulse dynamics is also taken into account. It is shown that injection at an angle can provide compressed and accelerated electron bunches with less than 2% energy spread. Another advantage of this scheme is that it has less stringent requirements in terms of the size of the injected bunch and there is the potential to trap more charge.

Download Full-text

Electron and photon beams interacting with plasma

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2005.1728 ◽

2006 ◽

Vol 364 (1840) ◽

pp. 635-645 ◽

Cited By ~ 2

Author(s):

Albert Reitsma ◽

Dino Jaroszynski

Keyword(s):

Laser Pulse ◽

Electron Bunch ◽

Laser Pulses ◽

Plasma Waves ◽

Intense Laser ◽

Wave Number ◽

Collective Effects ◽

Photon Beams ◽

Wave Dynamics ◽

Intense Laser Pulses

A comparison is made between the interaction of electron bunches and intense laser pulses with plasma. The laser pulse is modelled with photon kinetic theory , i.e. a representation of the electromagnetic field in terms of classical quasi-particles with space and wave number coordinates, which enables a direct comparison with the phase space evolution of the electron bunch. Analytical results are presented of the plasma waves excited by a propagating electron bunch or laser pulse, the motion of electrons or photons in these plasma waves and collective effects, which result from the self-consistent coupling of the particle and plasma wave dynamics.

Download Full-text

Coupling of longitudinal and transverse motion of accelerated electrons in laser wakefield acceleration

Laser and Particle Beams ◽

10.1017/s0263034604040054 ◽

2004 ◽

Vol 22 (4) ◽

pp. 407-413 ◽

Cited By ~ 11

Author(s):

A.J.W. REITSMA ◽

D.A. JAROSZYNSKI

Keyword(s):

Laser Pulse ◽

Group Velocity ◽

Electron Bunch ◽

Coupling Effect ◽

Energy Spread ◽

Transverse Motion ◽

Laser Wakefield Acceleration ◽

Wakefield Acceleration ◽

Laser Wakefield ◽

Wakefield Accelerator

The acceleration dynamics of electrons in a laser wakefield accelerator is discussed, in particular the coupling of longitudinal and transverse motion. This coupling effect is important for electrons injected with a velocity below the laser pulse group velocity. It is found that the electron bunch is adiabatically focused during the acceleration and that a finite bunch width contributes to bunch lengthening and growth of energy spread. These results indicate the importance of a small emittance for the injected electron bunch.

Download Full-text

Plasma guiding using a chaperone pre-pulse for stable wakefield generation

10.21203/rs.3.rs-679840/v1 ◽

2021 ◽

Author(s):

Devki Nandan Gupta ◽

Samuel Robert Yoffe ◽

Arohi Jain ◽

Bernhard Ersfeld ◽

Dino Anthony Jaroszynski

Keyword(s):

Laser Pulse ◽

Laser Pulses ◽

Space Distribution ◽

Essential Step ◽

Self Focusing ◽

Radiation Sources ◽

High Intensity Laser ◽

Laser Wakefield ◽

Intensity Laser ◽

Wakefield Accelerators

Abstract Achieving high quality electron beams in laser wakefield accelerators requires stable guiding of the intense driving laser pulse, which is challenging because of mode mismatching due to relativistic self-focusing. Here we show how an intense pre-pulse can be used to prepare the phase-space distribution of plasma electrons encountered by a trailing laser pulse so that it produces its own well-matched guiding channel, while minimising wakefield evolution. Controlling the propagation of high intensity laser pulses is an essential step in developing useful wakefield accelerators and compact radiation sources.

Download Full-text

Scissor-cross ionization injection in laser wakefield accelerators

Plasma Physics and Controlled Fusion ◽

10.1088/1361-6587/ac4853 ◽

2022 ◽

Author(s):

Jia Wang ◽

Ming Zeng ◽

Xiaoning Wang ◽

Dazhang Li ◽

Jie Gao

Keyword(s):

Three Dimensional ◽

Laser Pulses ◽

Acute Angle ◽

Energy Spread ◽

Particle In Cell ◽

High Injection ◽

Dope Ratio ◽

Laser Wakefield ◽

Driving Pulse ◽

Wakefield Accelerator

Abstract We propose to use a frequency doubled pulse colliding with the driving pulse at an acute angle to trigger ionization injection in a laser wakefield accelerator. This scheme effectively reduces the duration that injection occurs, thus high injection quality is obtained. Three-dimensional particle-in-cell simulations show that electron beams with energy of ~500 MeV, charge of ~40 pC, energy spread of ~1% and normalized emittance of a few millimeter milliradian can be produced by ~100 TW laser pulses. By adjusting the angle between the two pulses, the intensity of the trigger pulse and the gas dope ratio, the charge and energy spread of the electron beam can be controlled.

Download Full-text

Improvement of Properties of Self-Injected and Accelerated Electron Bunch by Laser Pulse in Plasma, Using Pulse Precursor

East European Journal of Physics ◽

10.26565/2312-4334-2019-2-10 ◽

2019 ◽

Keyword(s):

Laser Pulse ◽

Laser Plasma ◽

Electron Bunch ◽

Energy Spread ◽

Intense Laser ◽

X Rays ◽

Laser Wakefield Acceleration ◽

Small Energy ◽

Wakefield Acceleration ◽

Laser Wakefield

The accelerating gradients in conventional linear accelerators are currently limited to ~100 MV/m. Plasma-based accelerators have the ability to sustain accelerating gradients which are several orders of magnitude greater than that obtained in conventional accelerators. Due to the rapid development of laser technology the laser-plasma-based accelerators are of great interest now. Over the past decade, successful experiments on laser wakefield acceleration of electrons in the plasma have confirmed the relevance of this acceleration. Evidently, the large accelerating gradients in the laser plasma accelerators allow to reduce the size and to cut the cost of accelerators. Another important advantage of the laser-plasma accelerators is that they can produce short electron bunches with high energy. The formation of electron bunches with small energy spread was demonstrated at intense laser–plasma interactions. Electron self-injection in the wake-bubble, generated by an intense laser pulse in underdense plasma, has been studied. With newly available compact laser technology one can produce 100 PW-class laser pulses with a single-cycle duration on the femtosecond timescale. With a fs intense laser one can produce a coherent X-ray pulse. Prof. T. Tajima suggested utilizing these coherent X-rays to drive the acceleration of particles. When such X-rays are injected into a crystal they interact with a metallic-density electron plasma and ideally suit for laser wakefield acceleration. In numerical simulation of authors, performed according to idea of Prof. T.Tajima, on wakefield excitation by a X-ray laser pulse in a metallic-density electron plasma the accelerating gradient of several TV/m has been obtained. It is important to form bunch with small energy spread and small size. The purpose of this paper is to show by the numerical simulation that some precursor-laser-pulse, moved before the main laser pulse, controls properties of the self-injected electron bunch and provides at certain conditions small energy spread and small size of self-injected and accelerated electron bunch.

Download Full-text