Can lasers ignite fusion with protons? This paper assesses the conversion efficiency from intense picosecond laser pulses to multi-MeV ion beams, crucial for proton fast ignition in inertial confinement fusion (ICF). Utilizing 2D kinetic particle-in-cell simulations, the study examines a wide array of laser and target parameters, including quasi-one-dimensional geometry and conversion efficiency within a narrow spatial band along the laser axis. The findings address scalings while omitting beam divergence in the initial geometry. Large-scale 2D simulations then analyze conversion efficiency for flat and hemispherical targets. Combining these results enables the calculation of energy requirements for igniting a compressed ICF target using an intense proton beam in a fast-ignition scenario. Overall, this research enhances our understanding of laser-to-proton conversion efficiency, a critical factor for advancing fast-ignition fusion. Providing valuable insights into energy requirements. This helps to push the technology closer to practical application.
Published in Physics of Plasmas, this article aligns with the journal’s focus on plasma physics and its applications in fusion energy research. By studying laser-to-proton conversion efficiency, the research contributes to the understanding of fast-ignition scenarios, which is directly relevant to the journal’s coverage of plasma-based fusion technologies.