Nonlinear plasma wakefield acceleration: Models and experiments.

摘要

The work presented in this dissertation aims at a plasma-based high-energy physics application of the future; namely, the use of non-linear plasma waves to accelerate a beam of particles. Plasma wakefield acceleration is explored through 2-D and 3-D particle-in-cell (PIC) simulations, through physical models and finally through experiments. Special emphasis is given to the highly non-linear regime of interest for maximum acceleration and to acceleration of and by positron beams.; 2-D cylindrically symmetric numerical algorithm of a fully explicit Particle-in-Cell (PIC) code is introduced. The algorithm for curvilinear coordinates is presented briefly. After the introduction of modeling tools. The study of key issues on plasma-based acceleration using the simulation tools as well as the theoretical analysis is introduced. Computer simulation makes it possible to study various features in the nonlinear regime. The simulation and theoretical analysis results for the important phenomena of interest, such as ion motion and the effect of transverse plasma density gradients in the beam-driven plasma wakefield accelerator (PWFA) are presented. The results of two- and three-dimensional particle-in-cell (PIC) computer simulations are shown.; Then, the demonstration of PWFA experiment “One-meter-long plasma wakefield acceleration (E-157)” that was carried out at the Stanford Linear Accelerator Center (SLAG) is introduced. The comparison and the analysis between experimental results and the numerical simulations are shown. The betatron oscillations of the electron bunch and collective refraction of an electron beam at the plasma-gas interface have been witnessed in this PWFA experiment.; The modeling of particle acceleration is further extended by including positron-driven PWFAs. Both electron- and positron-driven PWFAs are compared to establish the analogy and the differences in the nonlinear regime. The possibility of enhancing the electron plasma wave driven by the positron bunch is investigated.; Furthermore, the afterburner concept for an energy booster for a future electron-positron collider is introduced. A novel scenario of employing a few-meters-long plasma section as an afterburner and a final focusing-element to boost the energy of each bunch of a collider and focus them just prior to collision is proposed. Issues associated with a self-consistent design for a high-energy collider to seek the Higgs boson and the ultimate test of the Standard Model in high-energy physics above 100 GeV are addressed.