COMPACT LASER DRIVEN ELECTRON AND PROTON ACCELERATION WITH LOW ENERGY LASERS

Abstract

Laser-driven particle accelerators offer many advantages over conventional particle

accelerators. The most significant of these is the magnitude of the accelerating

gradient and, consequently, the compactness of the accelerating structure. In this

dissertation, experimental and computational advances in laser-based particle

acceleration in three intensity regimes are presented. All mechanisms investigated

herein are accessible by “tabletop” ultrashort terawatt-class laser systems found in

many university labs, with the intention of making them available to more compact

and high repetition rate laser systems. The first mechanism considered is the

acceleration of electrons in a preformed plasma “slow-wave” guiding structure.

Experimental advances in the generation of these plasma guiding structures are

presented. The second mechanism is the laser-wakefield acceleration of electrons in

the self-modulated regime. A high-density gas target is implemented experimentally

leading to electron acceleration at low laser pulse energy. Consequences of operating

in this regime are investigated numerically. The third mechanism is the acceleration

of protons by a laser-generated magnetic structure. A numerical investigation is

performed identifying operating regimes for experimental realizations of this

mechanism. The key advances presented in this dissertation are:

 The development and demonstration of modulated plasma waveguide

generation using both mechanical obstruction and an interferometric laser

patterning method

 The acceleration of electrons to MeV energy scales in a high-density

hydrogen target with sub-terawatt laser pulses and the generation of bright,

ultra-broadband optical pules from the interaction region

 3D particle-in-cell (PIC) simulations of self-modulated laser wakefield

acceleration in a plasma, showing the generation of broadband radiation, and

the role of “direct laser acceleration” in this regime

 3D PIC simulations of laser wakefield acceleration in the resonant regime,

identifying spatio-temporal optical vortices in a laser-plasma system

 3D PIC simulations of proton acceleration by magnetic vortex acceleration

using TW-class laser pulses