Laser Fusion Chamber Design

Abstract

A laser fusion chamber must absorb the energy emitted by the target in such a way that the plant can achieve a commercially viable power conversion efficiency. This must be accomplished with a design that can reliably withstand on the order of a billion shots. For a dry chamber wall, the key lifetime issues are thermo-mechanical effects resulting from the rapid heating, ion effects, such as blistering and sputtering, and radiation effects. These issues define the chamber size by providing flux limits for the various threats. In cases where a dry, unprotected wall cannot provide an adequate lifetime, measures must be taken to reduce the threat to the wall. Previously proposed approaches include filling the chamber with sufficient gas to stop the majority of the ions before they reach the wall or redirection of the ions by a cusp field. Other design trade-offs that must be addressed include the need to reduce heating of the target during injection and the need for adequate clearing of the chamber between shots. In this paper we provide a review of the chamber design approaches required for commercially viable laser fusion power plants, the issues driving those designs, and some system-level analyses that provide insight into the implications of these design issues for the overall economics of a commercial plant.