scholarly journals Ion-channel laser growth rate and beam quality requirements

2018 ◽  
Vol 84 (3) ◽  
Author(s):  
X. Davoine ◽  
F. Fiúza ◽  
R. A. Fonseca ◽  
W. B. Mori ◽  
L. O. Silva
Keyword(s):  
Growth Rate ◽  
Electron Beam ◽  
Ion Channel ◽  
Beam Quality ◽  
Three Dimensional ◽  
Quality Requirements ◽  
Particle In Cell ◽  
Theoretical Predictions ◽  
First Time ◽  
Wakefield Accelerator

In this paper, we determine the growth rate of the exponential radiation amplification in the ion-channel laser, where a relativistic electron beam wiggles in a focusing ion channel that can be created in a wakefield accelerator. For the first time the radiation diffraction, which can limit the amplification, is taken into account. The electron beam quality requirements to obtain this amplification are also presented. It is shown that both the beam energy and wiggler parameter spreads should be limited. Two-dimensional and three-dimensional particle-in-cell simulations of the self-consistent ion-channel laser confirm our theoretical predictions.

scholarly journals Scissor-cross ionization injection in laser wakefield accelerators

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.

scholarly journals Space-time evolution of electron-beam driven electron holes and their effects on the plasma

2003 ◽  
Vol 10 (1/2) ◽  
pp. 53-63 ◽  
Author(s):  
N. Singh
Keyword(s):  
Electron Beam ◽  
Plasma Density ◽  
Three Dimensional ◽  
Low Frequency ◽  
Velocity Distribution Function ◽  
Lower Hybrid ◽  
Particle In Cell ◽  
Short Transverse ◽  
Electron Holes ◽  
Number Of Electron Holes

Abstract. We report here further results from the three-dimensional particle-in-cell simulations of the electron-beam driven electron holes. We focus here on (i) the transformation of oscillatory waves driven by the electron-beam instability into electron holes, (ii) the continued evolution and propagation of electron holes after their formation, including merging of electron holes, and (iii) the effects of the evolution on the plasma density and ion velocity distribution function. We find that initially electron-beam modes with perpendicular wave numbers k^ = 0 and as well as k^ ≠ 0 are driven resonantly below the electron plasma frequency of the target plasma. The modes interact nonlinearly and modulate each other both in space and time, producing wave structures with finite perpendicular scale lengths. Nonlinear evolution of such wave structures generates the electron holes in the simulations. Initially, a large number of electron holes form in the plasma. Their merging yields continuously a decreasing number of electron holes. The propagation velocity of the electron holes evolves dynamically and is affected by their merging. At late times only a few electron holes are left in the simulation and they decay by emitting low-frequency electrostatic whistler waves just above the lower hybrid (LH) frequency vlh . These waves, which are long structures parallel to the ambient magnetic field B0 and quite short transverse to B0, are associated with similar structures in the plasma density, producing density filaments. It turns out that electron-beam driven plasmas, in general, develop such filaments at some stage of the evolution of the beam-driven waves. In view of the excitation of the LH waves near vlh, which could resonate with the ions, an analysis shows that it is possible to heat transversely the ions in a time scale of a few seconds in the auroral return current plasma, in which electron holes and transversely heated ions have been simultaneously observed.

scholarly journals Optical control of transverse motion of ionization injected electrons in a laser plasma accelerator

2021 ◽  
Vol 9 ◽  
Author(s):  
Jie Feng ◽  
Yifei Li ◽  
Jinguang Wang ◽  
Dazhang Li ◽  
Changqing Zhu ◽  
...  
Keyword(s):  
Electron Beam ◽  
Laser Plasma ◽  
Optical Method ◽  
Three Dimensional ◽  
Plasma Accelerator ◽  
Transverse Motion ◽  
Particle In Cell ◽  
Laser Focus ◽  
All Optical ◽  
Laser Plasma Accelerator

Abstract We demonstrate an all-optical method for controlling the transverse motion of an ionization injected electron beam in a laser plasma accelerator by using the transversely asymmetrical plasma wakefield. The laser focus shape can control the distribution of a transversal wakefield. When the laser focus shape is changed from circular to slanted elliptical in the experiment, the electron beam profiles change from an ellipse to three typical shapes. The three-dimensional particle-in-cell simulation result agrees well with the experiment, and it shows that the trajectories of these accelerated electrons change from undulating to helical. Such an all-optical method could be useful for convenient control of the transverse motion of an electron beam, which results in synchrotron radiation from orbit angular momentum.

Ion-Focused Propagation of Relativistic Electron Beam in the Self-Generated Plasma in the Atmosphere

2022 ◽  
Author(s):  
Hao Jian-Hong ◽  
Xue Bi-Xi ◽  
Zhao Qiang ◽  
Zhang Fang ◽  
Fan Jie-Qing ◽  
...  
Keyword(s):  
Electron Beam ◽  
Relativistic Electron ◽  
Long Range ◽  
Relativistic Electron Beam ◽  
Beam Quality ◽  
Pulse Length ◽  
Space Environment ◽  
Long Distance ◽  
Particle In Cell ◽  
Neutral Gas

Abstract It is known that ion-focused regime can effectively suppress the expansion of relativistic electron beam (REB). By using particle in cell-Monte Carlo collision (PIC-MCC) method, the propagation of REBs in neutral gas is numerically investigated. The numerical results demonstrate that the beam body is charge neutralization and a stable IFR can be established. As a result, the beam transverse dimensions and longitudinal velocities keep close to the initial parameters. We also calculated the charge and current neutralization factors of REBs. Combined with envelope equations, we obtained the variations of beam envelopes, which agree well with the PIC simulations. However, both the energy loss and instabilities of REBs may lead to a low transport efficiency during long-range propagation. It has been proved that decreasing the initial pulse length of REBs can avoid the influence of electron avalanche. Using parts of REB pulses to build a long-distance IFR in advance can improve the beam quality of subsequent pulses. Further, a long-distance IFR may contribute to the implementation of long-range propagation of REBs in the space environment.

Electron trapping and acceleration in plasma wake field produced by an evolving hollow electron beam

2021 ◽  
Vol 87 (1) ◽  
Author(s):  
Xiangyang Liu ◽  
Junfan Qu ◽  
Peng Liu ◽  
Houchen Fan ◽  
Ling Cai ◽  
...  
Keyword(s):  
Electron Beam ◽  
Beam Quality ◽  
Initial Energy ◽  
Electron Trapping ◽  
Particle In Cell ◽  
Hollow Beam ◽  
Electron Bubble ◽  
Wake Field ◽  
Transformer Ratio ◽  
Hollow Electron Beam

In this article, the electron trapping and acceleration in the wake field driven by an ultrarelativistic hollow electron beam is studied. When the hollow driver injects into plasma, there is a doughnut-shaped electron bubble formed because of the existence of a special ‘backflow’ beam in the centre of the electron bubble. At the same time, there is a transverse convergence of the hollow driver, which leads to the weakening of the backflow beam. This results in a local electron density transition at the rear of the bubble. During this process, there is an expansion of the longitudinal electron bubble size, and a bunch of background electrons is trapped by the wake field at the rear of the bubble. The tracks for the trapped electrons show that there are two sources: one is from the bubble sheath and the other is from the unique backflow beam. In the particle-in-cell simulation where the driving beam has initial energy of $1.0$ GeV per particle, the trapped beam can be accelerated to energy of more than $1.5$ GeV per particle and the corresponding transformer ratio is $1.5$ . With the increase of driving beam energy up to $40.0$ GeV, a transformer ratio of $1.4$ still can be achieved. By adjusting the hollow beam density, it is possible to control the trapped beam charge value and beam quality, such as its energy spread and transverse emittance.

scholarly journals Optimization of Electron Beams Based on Plasma-Density Modulation in a Laser-Driven Wakefield Accelerator

2021 ◽  
Vol 11 (6) ◽  
pp. 2560
Author(s):  
Lintong Ke ◽  
Changhai Yu ◽  
Ke Feng ◽  
Zhiyong Qin ◽  
Kangnan Jiang ◽  
...  
Keyword(s):  
Shock Wave ◽  
Electron Beams ◽  
Three Dimensional ◽  
Mean Square ◽  
High Reproducibility ◽  
Practical Applications ◽  
Particle In Cell ◽  
Laser Wakefield ◽  
Density Modulation ◽  
Wakefield Accelerator

We demonstrate a simple but efficient way to optimize and improve the properties of laser-wakefield-accelerated electron beams (e beams) based on a controllable shock-induced density down-ramp injection that is achieved with an inserted tunable shock wave. The e beams are tunable from 400 to 800 MeV with charge ranges from 5 to 180 pC. e beams with high reproducibility (of ~95% in consecutive 100 shots) were produced in elaborate experiments with an average root- mean-square energy spread of 0.9% and an average divergence of 0.3 mrad. Three-dimensional particle-in-cell (PIC) simulations were also performed to accordingly verify and uncover the process of the injection and the acceleration. These tunable e beams will facilitate practical applications for advanced accelerator beam sources.

scholarly journals Transitions to three-dimensional flows in a cylinder driven by oscillations of the sidewall

2011 ◽  
Vol 681 ◽  
pp. 515-536 ◽  
Author(s):  
C. PANADES ◽  
F. MARQUES ◽  
J. M. LOPEZ
Keyword(s):  
Bluff Body ◽  
Travelling Waves ◽  
Three Dimensional ◽  
Careful Analysis ◽  
Theoretical Predictions ◽  
Spatio Temporal ◽  
Nonlinear Solutions ◽  
First Time ◽  
Temporal Symmetry ◽  
Codimension Two Bifurcation

The transition from two-dimensional to three-dimensional flows in a finite circular cylinder driven by an axially oscillating sidewall is explored in detail. The complete symmetry group of this flow, including a spatio-temporal symmetry related to the oscillating sidewall, is Z2 × O(2). Previous studies in flows with the same symmetries, such as symmetric bluff-body wakes and periodically forced rectangular cavities, were unable to obtain the theoretically predicted bifurcation to modulated travelling waves. In the simpler cylindrical geometry, where the azimuthal direction is physically periodic, we have found these predicted modulated travelling waves as stable fully saturated nonlinear solutions for the first time. A careful analysis of the base states and their linear stability identifies different parameter regimes where three-dimensional states are either synchronous with the forcing or quasi-periodic, corresponding to different symmetry-breaking processes. These results are in good agreement with theoretical predictions and previous results in similar flows. These different regimes are separated by three codimension-two bifurcation points that are yet to be fully analysed theoretically. Finally, the saturated nonlinear states and their properties in different parameter regimes are analysed.

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