Injection and acceleration of electron bunch in a plasma wakefield produced by a chirped laser pulse

Afhami, Saeedeh; Eslami, Esmaeil

doi:10.1063/1.4884792

Cited by 12 publications

(5 citation statements)

References 25 publications

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“…The under-dense hydrogen plasma (T e = 0) is initially located in the region of 30 µm < x < 175 µm, −30 µm < y < 30 µm with the density of n e = 0.02n c , where n c = 1.1 × 10 21 cm −3 is the critical density for the laser pulse with a wave length of λ Laser = 1 µm. The electric field of the chirped laser pulse that propagates along the x axis can be expressed as [43] 𝐸 Laser (y,…”

Section: Theory and Simulation Parametersmentioning

confidence: 99%

Pulse chirping effect on controlling the transverse cavity oscillations in nonlinear bubble regime

et al. 2017

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The propagation of an intense laser pulse in an under-dense plasma induces a plasma wake that is suitable for the acceleration of electrons to relativistic energies. For an ultra-intense laser pulse which has a longitudinal size shorter than the plasma wavelength, λ p , instead of a periodic plasma wave, a cavity free from cold plasma electrons, called a bubble, is formed behind the laser pulse. An intense charge separation electric field inside the moving bubble can capture the electrons at the base of the bubble and accelerate them with a narrow energy spread. In the nonlinear bubble regime, due to localized depletion at the front of the pulse during its propagation through the plasma, the phase shift between carrier waves and pulse envelope plays an important role in plasma response. The carrier-envelope phase (CEP) breaks down the symmetric transverse ponderomotive force of the laser pulse that makes the bubble structure unstable. Our studies using a series of two-dimensional (2D) particle-in-cell (PIC) simulations show that the frequency-chirped laser pulses are more effective in controlling the pulse depletion rate and consequently the effect of the CEP in the bubble regime. The results indicate that the utilization of a positively chirped laser pulse leads to an increase in rate of erosion of the leading edge of the pulse that rapidly results in the formation of a steep intensity gradient at the front of the pulse. A more unstable bubble structure, the self-injections in different positions, and high dark current are the results of using a positively chirped laser pulse. For a negatively chirped laser pulse, the pulse depletion process is compensated during the propagation of the pulse in plasma in such a way that results in a more stable bubble shape and therefore, a localized electron bunch is produced during the acceleration process. As a result, by the proper choice of chirping, one can tune the number of self-injected electrons, the size of accelerated bunch and its energy spectrum to the values required for practical applications.

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Section: Theory and Simulation Parametersmentioning

confidence: 99%

Pulse chirping effect on controlling the transverse cavity oscillations in nonlinear bubble regime

et al. 2017

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“…In LWFA, the laser pulse with PFT will excite asymmetric wakefield which will force the pulse to deviate from its initial axis and alter the way the electrons are injected and accelerated [11,17,18]. In the community, it is well known that the influence of GDD on the electron accelerating process has been studied and many groups use the algorithms to manage electron beam optimization [19,20]. However, the controlling over the pointing direction of high energy electron beams by GDD has not been reported yet.…”

Section: Introductionmentioning

confidence: 99%

Optical steering of electron beam in laser plasma accelerators

Zhu

Wang

et al. 2020

Opt. Express

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By using Dazzler system and tilting compressor grating, we provide an effective way of using the laser group delay dispersion (GDD) to continuously steer the high energy electron beam which is accelerated by asymmetric laser-wakefield. The deviation angle of electrons is as the same as the angular chirped laser pulse from its initial optical axis, which is determined by the laser pulse-front-tilt (PFT). This unique method can be continuously used to control over the pointing direction of electron-pulses to the requisite trajectories, especially for the alignment sensitive devices such as electron-positron collider or undulator. Besides, the effect of PFT on the qualities of electron beam has been investigated.

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“…With regard to frequency chirping and pulse shape, theoretical and experimental studies have shown that a positive chirp with a fast-rising leading edge can increase self-trapping of electrons by increasing the wakefield amplitude generated by the chirped pulse. The higher amplitude wakefield then serves to decrease the minimum momentum required to trap electrons [11][12][13][14][15][16][17][18][19][20]. On the other hand, simulations have shown that incoherently stacking negatively chirped pulses of different wavelengths can be used to create electron beams with energies higher than that obtained using optimally compressed pulses.…”

Section: Introductionmentioning

confidence: 99%

Characterization of electrons and x-rays produced using chirped laser pulses in a laser wakefield accelerator

Zhao¹,

Behm²,

He³

et al. 2016

Plasma Phys. Control. Fusion

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The electron injection process into a plasma-based laser wakefield accelerator can be influenced by modifying the parameters of the driver pulse. We present an experimental study on the combined effect of the laser pulse duration, pulse shape, and frequency chirp on the electron injection and acceleration process and the associated radiation emission for two different gas types-a 97.5% He and 2.5% N 2 mixture and pure He. In general, the shortest pulse duration with minimal frequency chirp produced the highest energy electrons and the most charge. Pulses on the positive chirp side sustained electron injection and produced higher charge, but lower peak energy electrons, compared with negatively chirped pulses. A similar trend was observed for the radiant energy. The relationship between the radiant energy and the electron charge remained linear over a threefold change in the electron density and was independent of the drive pulse characteristics. X-ray spectra showed that ionization injection of electrons into the wakefield generally produced more photons than self injection for all pulse durations/frequency chirp and had less of a spread in the number of photons around the peak X-ray energy.

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Injection and acceleration of electron bunch in a plasma wakefield produced by a chirped laser pulse

Cited by 12 publications

References 25 publications

Pulse chirping effect on controlling the transverse cavity oscillations in nonlinear bubble regime

Pulse chirping effect on controlling the transverse cavity oscillations in nonlinear bubble regime

Optical steering of electron beam in laser plasma accelerators

Characterization of electrons and x-rays produced using chirped laser pulses in a laser wakefield accelerator

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