Present Status and Future Prospects of Light Ions as Drivers for Inertial Fusion

摘要

Light ion beams offer a low cost (50 to 80 $/J for repetitive driver), 20% efficient driver for Inertial Confinement Fusion (ICF). Since the ions deposit their energy in a dense (10 sup 22 electrons/cm sup 3 ) plasma and are shielded from each other, collective effects and the associated preheating electrons are avoided. Power concentration has been the dominant problem. In 1984, a proof-of-principle experiment demonstrated an intense ion beam with adequate beam divergence (15 mrad) at the source current and charge density required for fusion. In 1985, the result was scaled to the total current and source dimensions required for ignition, and the Particle Beam Fusion Accelerator II (PBFA II) was completed. PBFA II is designed to generate and focus a lithium ion beam onto a spherical target at 100 TW/cm sup 2 , investigate ignition, and explore the technology required for high gain targets. The principal research topics for the light ion approach have been the generation of a sufficiently powerful electrical pulse, the transformation of that electrical energy into particle beam energy, the focusing of the beam to the few-millimeter diameter, and the transport of the beam to a target at some distance from the source. Substantial progress has been made on all of these areas and the perceived risk of the light ion approach has been substantially reduced. (ERA citation 11:035313)