The physics issues that determine inertial confinement fusion target gain and driver requirements : A tutorial *

This paper presents a simplified, tutorial approach to determining the gains of inertial confinement fusion ~ICF! targets, via a basic, zero-dimensional ~‘‘0-D’’!, energy ‘‘bookkeeping’’ of input ~parametrized by ICF drivers’ coupling efficiencies to the target, and subsequent hydrodynamic efficiencies of implosion! versus output ~thermonuclear burn efficiency and target fuel mass!. Physics issues/constraints such as hydrodynamic instabilities, symmetry and implosion velocity requirements will be discussed for both the direct drive ~driver impinging directly on the target! and indirect drive ~x-ray implosion within a driver heated hohlraum! approaches to ICF. Supplementing the 0-D model with simple models for hohlraum wall energy loss ~to predict coupling efficiencies! and a simple one-dimensional ~1-D! model of the implosion as a spherical rocket ~to predict hydrodynamic implosion efficiencies! allows gains to be predicted that compare well with the results of complex two-dimensional ~2-D! radiation hydrodynamic simulations. © 1999 American Institute of Physics. @S1070-664X~99!92205-X#