Large-Fluence Laser-Driven Ion Beam for Inertial Fusion Ignition

Abstract

As a prospective approach for inertial confinement fusion, fast ion ignition may achieve high gain with low driver energy and simple target fabrication. However, studies show that fast ion ignition requires an ion beam with extremely large energy fluence and high quality. In comparison with conventional accelerators, laser-driven ion accelerators have advantages of compact size, high density, and short bunch duration. Nevertheless, it is still challenging to simultaneously enhance the yield and quality of laser-driven ion beams for fast ion ignition. In this work, we propose a scheme to address this challenge. First, the ions of a target can be uniformly accelerated in hole-boring radiation pressure acceleration by matching the laser intensity profile with the target density profile. Second, the oscillation of the electric field for ion acceleration can be effectively suppressed by using two-ion-species targets. Particle-in-cell (PIC) simulation demonstrates that almost all ions in a solid target of a few microns can be uniformly accelerated to relativistic speeds by using our scheme. The resulting ion beam with large energy fluence and high quality may drive fusion ignition and more generally create matter with unprecedented high-energy density.