The self-injection threshold in self-guided laser wakefield accelerators

Abstract

A laser pulse traveling through a plasma can excite large amplitude plasma waves that can be used to accelerate relativistic electron beams in a very short distance---a technique called laser wakefield acceleration. Many wakefield acceleration experiments rely on the process of wavebreaking, or self-injection, to inject electrons into the wave, while other injection techniques rely on operation without self-injection. We present an experimental study into the parameters, including the pulse energy, focal spot quality and pulse power, that determine whether or not a wakefield accelerator will self-inject. By taking into account the processes of self-focusing and pulse compression we are able to extend a previously described theoretical model, where the minimum bubble size required for trapping is not constant but varies slowly with density and find excellent agreement with this model.

5 pages

References in corpus (4)

• Generating multi-GeV electron bunches using single stage laser wakefield acceleration in a 3D nonlinear regime
• Electron Self-injection in Multidimensional Relativistic Plasma Wakefields
• The Effect of Laser Focusing Conditions on Propagation and Monoenergetic Electron Production in Laser Wakefield Accelerators
• Controlling the spectrum of x-rays generated in a laser-plasma accelerator by tailoring the laser wavefront

Cited by in corpus (9)

• Direct observation of the injection dynamics of a laser wakefield accelerator using few-femtosecond shadowgraphy
• High-charge relativistic electron bunches from a kHz laser-plasma accelerator
• Control of electron beam current, charge and energy spread using density downramp injection in laser wakefield accelerators
• Direct laser acceleration of electrons in high-Z gas target and effect of threshold plasma density on electron beam generation
• Bright X-ray radiation from plasma bubbles in an evolving laser wakefield accelerator
• Positron acceleration via laser-augmented blowouts in two-column plasma structures
• Laser wakefield acceleration with high-power, few-cycle mid-IR lasers
• Characterisation of Laser Wakefield Acceleration Efficiency with Octave Spanning Near-IR Spectrum Measurements
• Electron self-injection threshold for the tandem-pulse laser wakefield accelerator