Control of electron beam current, charge and energy spread using density downramp injection in laser wakefield accelerators

Abstract

Density dowmramp injection has been demonstrated to be an elegant and efficient approach for generating high quality electron beams in laser wakefield accelerators. Yet, the charge of the produced beam is tens of pC per Joule of laser energy, still limiting its use for a wider range of applications. The possibility of generating high charge beam while keeping a good beam quality, stays to be explored. Moreover, despite previous studies focused on separate physical processes such as beam loading which affects the uniformity of the acceleration field and thus the energy spread of the trapped electrons, repulsive force from the rear spike of the bubble which reduces the transverse momentum $p_{\perp }$ of the trapped electrons and results in small beam emmittance, and the laser evolution when travelling in plasma. A more general investigation of the plasma density parameters on the final beam properties is required. In this work, we demonstrate that the current profile of the injected electron beam is directly correlated with the density transition parameters, which further affects the beam charge and energy spread. By fine-tuning the plasma density parameters, high-charge (up to several hundreds of pC) and low-energy-spread (around 1\% FWHM) electron beams can be obtained. All these results are supported by large-scale three-dimensional particle-in-cell simulations.

arXiv comment15 pages, 11 figures

References in corpus (8)

• Generating multi-GeV electron bunches using single stage laser wakefield acceleration in a 3D nonlinear regime
• A spectral, quasi-cylindrical and dispersion-free Particle-In-Cell algorithm
• Beam loading in the nonlinear regime of plasma-based acceleration
• Electron Self-injection in Multidimensional Relativistic Plasma Wakefields
• Demonstration of a compact plasma accelerator powered by laser-accelerated electron beams
• The self-injection threshold in self-guided laser wakefield accelerators
• High quality electron bunch generation using a longitudinal density-tailored plasma-based accelerator in the three-dimensional blowout regime
• Stable and high quality electron beams from staged laser and plasma wakefield accelerators

Cited by in corpus (3)

• An analytical optimization of plasma density profiles for downramp injection in laser wake-field acceleration
• Simulation Study of Energy Chirp Induced Effects in Laser Wakefield Accelerator Driven Free Electron Laser
• Beam current from downramp injection in electron-driven plasma wakefields