%0 Journal Article
%T The self-injection threshold in self-guided laser wakefield accelerators
%A Stuart P. D. Mangles
%A Guillaume Genoud
%A Michael S. Bloom
%A Matthias Burza
%A Zulfikar Najmudin
%A Anders Persson
%A Kristoffer Svensson
%A Alexander G. R. Thomas
%A Claes-Goran Wahlstrom
%J Physics
%D 2012
%I arXiv
%R 10.1103/PhysRevSTAB.15.011302
%X 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.
%U http://arxiv.org/abs/1201.1149v1