Advanced Simulations And Optimization Of Intense Laser Interactions PDF Download

High-energy (100s MeV), high spectral quality ion beams are important for many applications like radiography of plasmas, isochoric heating of materials, and tumor therapy. Advances in the development of intense short pulse lasers, recognized with the 2018 Nobel Prize in physics, have been seen as a very promising route to drive compact ion beam sources. However, despite signficant progress over the past two decades, the control of the ion beam properties remains an outstanding challenge. In this Thesis, we discuss two approaches for controlling and optimizing these laser-driven ion beams, using particle-in-cell simulations and theoretical analysis. First, we show that in laser radiation pressure acceleration, the spectral quality of the ion beam is determined by electron heating, which is dictated by the growth of a surface instability. We show that its growth rate imposes an upper limit on the laser pulse duration, and can limit the maximum peak ion beam energy. Next, we explore the development of a hybrid accelerator that combines the advantages of laser-driven beams (compact, high-charge, 10s MeV) with high-gradient RF acceleration in a meter-scale linac, eliminating the large and expensive radio frequency quadrupoles for bunching. Our one-to-one simulations show that the space-charge field plays a critical role in the acceleration effectiveness, and that by tuning the distance at which the laser-driven beam enters the RF, the space-charge field can be controlled such that it actually increases the beam capture. These are important in guiding future experimental developments, for example for the ultrashort laser pulses at state-of-the-art laser facilities and high-gradient linacs, for which we showcase the possibility of a compact (4.5 m) hybrid accelerator that produces a high-quality, high-charge 250 MeV proton beam.