Current activities (last few years) at different laboratories, towards the development of a laser wakefield accelerator (LWFA) are reviewed, followed by a more in depth discussion of results obtained at the L'OASIS laboratory of LBNL. Recent results on laser guiding of relativistically intense beams in preformed plasma channels are discussed. The observation of mono-energetic beams in the 100 MeV energy range, produced by a channel guided LWFA at LBNL, is described and compared to results obtained in the unguided case at LOA, RAL and LBNL. Analysis, aided by particle-in-cell simulations, as well as experiments with various plasma lengths and densities, indicate that tailoring the length of the accelerator has a very beneficial impact on the electron energy distribution. Progress on laser triggered injection is reviewed. Results are presented on measurements of bunch duration and emittance of the accelerated electron beams, that indicate the possibility of generating femtosecond duration electron bunches. Future challenges and plans towards the development of a 1 GeV LWFA module are discussed.

Laser plasma accelerators (LPAs) have shown promise as the next generation of compact particle accelerators. When a high intensity laser pulse propagates through a plasma, the laser can drive a large-amplitude wave which supports accelerating and focusing electric fields. Acceleration gradients three orders of magnitude greater than those found in conventional accelerators have been demonstrated. However, before an LPA-based high energy collider can be built, several advancements are still necessary, including further increases in beam energy and improvements in beam quality.

While electron beams have been accelerated to 8 GeV in a 20 cm LPA, the energy gain in a single LPA stage is limited by the laser energy available. To reach the energies needed for high energy physics, coupling of many LPAs is required. In addition, the beams must be injected and accelerated with high beam quality to reach the luminosities needed at the collision point to produce enough events to search for new physics. While enormous progress has been seen in the acceleration of electrons, positron acceleration is more challenging because most of the existing LPA structures are less suitable for positively charged particles.

In this thesis, we demonstrate staging of two laser plasma accelerators, injecting electrons in one stage and post-accelerating them in a second. We discuss the development of a high-quality injector stage and demonstrate techniques for controlling the injected electron beam parameters by modifying the plasma density profile. Finally, we detail a novel LPA structure which has demonstrated low-power laser guiding and has the potential to accelerate both electrons and positrons with high quality.

A summary is given of presentations and discussions in the Laser-Plasma Acceleration Working Group at the 2006 Advanced Accelerator Concepts Workshop. Presentation highlights include: widespread observation of quasi-monoenergetic electrons; good agreement between measured and simulated beam properties; the first demonstration of laser-plasma acceleration up to 1 GeV; single-shot visualization of laser wakefield structure; new methods for measuring < 100 fs electron bunches; and new methods for "machining" laser-plasma accelerator structures. Discussion of future direction includes: developing a roadmap for laser-plasma acceleration beyond 1 GeV; a debate over injection and guiding; benchmarking simulations with improved wake diagnostics; petawatt laser technology for future laser-plasma accelerators.

Unlike conventional accelerators, the accelerating structure in a laser plasma accelerator (LPA) is dynamically created by the interaction of a high-peak-power laser pulse with a plasma target. This dynamic nature allows extensive control over the acceleration process but requires detailed knowledge and regulation of the laser, the plasma target, and their interaction. In this thesis, the effect of laser pulse structure, in particular temporal profile and spatiotemporal coupling, on laser plasma acceleration is investigated through theoretical models and experiments at the BErkeley Laboratory Laser Accelerator (BELLA) Center. The temporal profile of the laser and the density profile of the plasma target are probed by laser spectral shifting. A novel model of laser steering and electron beam deflection due to pulse front tilt is developed. The effects of pulse front tilt are measured in experiments and found to be in good agreement with the theoretical model. The application of these results for the optimization of a laser plasma accelerator is discussed.