Compact Particle Accelerators Using High Gradient Laser Wakefields

Laser driven wakefield accelerators produce accelerating fields thousands of times those achievable in conventional radiofrequency accelerators, potentially extending the frontiers of high energy physics and enabling laboratory scale ultrafast radiation sources. Because the plasma response is highly nonlinear, large-scale, self consistent particle simulations in 3D are important to understand and optimize this new acceleration process. Such simulations have shown that high quality electron bunches in recent LBNL and other experiments were formed by self trapping of electrons in the wake followed by loading of the wake by the trapped bunch, creating a bunch of electrons isolated in phase space.

A narrow energy spread beam was then obtained by extracting the bunch as it outran the accelerating phase of the wake. These simulations have now been extended to three dimensions and high resolution under INCITE to provide more quantitative understanding of the experiments. Challenges now include control and reproducibility of the electron beam, further improvements in energy spread, and scaling to higher energies. Experiments and simulations are also in progress to control injection of particles into the wake and hence improve beam quality and stability further.