Structured laser-plasma interactions at ultra-high intensities

Laser-plasma interactions at ultra-high intensities provide a powerful platform for accelerating charged particles to high energies (10s−100sMeV) over microscopic distances, offering a promising alternative to conventional accelerators. High-energy protons and electrons play a crucial role in applications such as microscopy, advanced radiation sources, medical treatments, and high-energy-density physics. Advances in laser technology enable the generation of structured beams beyond Gaussian profiles at ultra-high intensities.

Tailored phase, polarization, and spatiotemporal coupling introduce new degrees of freedom to manipulate plasma dynamics. This thesis employs theoretical modeling and three-dimensional particle-in-cell simulations to investigate the role of structured lasers in unlocking novel mechanisms for compact particle accelerators. The first objective is to generate collimated high-energy proton beams. We explore effects such as reduced relativistic self-focusing through advanced target designs and support experimental findings on twisted laser-driven proton acceleration, bridging theory, simulations, and experiments.

Furthermore, we examine angular momentum gain in plasma electrons under different conditions. We identify a mechanism in which local pump depletion of a laser with azimuthal polarization—but no net angular momentum—facilitates electron rotation. Additionally, angular momentum transfer from lasers carrying spin and orbital angular momentum is analyzed across different plasma regimes, demonstrating their role in generating substantial magnetic fields.