Review of progress in Fast Ignition

TLDR

Marshall Rosenbluth’s work on laser‑plasma physics and inertial fusion, combined with his support of Fast Ignition—a scheme that compresses fuel with a conventional driver and ignites it with a short, high‑power laser pulse enabled by recent laser‑technology advances—frames this review. This review evaluates ignition requirements and gain curves from simple to detailed models, explores how to efficiently assemble compressed fuel and deliver driver power to the ignition region, discusses methods to shorten the distance between the critical surface and ignition region, and outlines future research directions. The current status of Fast Ignition research is compared with the requirements for success.

Abstract

Marshall Rosenbluth’s extensive contributions included seminal analysis of the physics of the laser-plasma interaction and review and advocacy of the inertial fusion program. Over the last decade he avidly followed the efforts of many scientists around the world who have studied Fast Ignition, an alternate form of inertial fusion. In this scheme, the fuel is first compressed by a conventional inertial confinement fusion driver and then ignited by a short (∼10ps) pulse, high-power laser. Due to technological advances, such short-pulse lasers can focus power equivalent to that produced by the hydrodynamic stagnation of conventional inertial fusion capsules. This review will discuss the ignition requirements and gain curves starting from simple models and then describe how these are modified, as more detailed physics understanding is included. The critical design issues revolve around two questions: How can the compressed fuel be efficiently assembled? And how can power from the driver be delivered efficiently to the ignition region? Schemes to shorten the distance between the critical surface where the ignitor laser energy is nominally deposited and the ignition region will de discussed. The current status of Fast Ignition research is compared with our requirements for success. Future research directions will also be outlined.