Inertial confinement fusion – physics principles

In inertial confinement fusion (ICF) energy is released in impulsive form from a small amount (a few milligrams, at most) of strongly compressed and hot fuel. Inertial fusion energy (IFE) production will be obtained from the sequential burn of targets, at a rate of the order of a few Hz. For economical IFE each target must achieve significant energy gain, defined as the ratio of the released fusion energy to the energy spent to bring the fuel to fusion conditions. In this chapter, key physics concepts for the achievement of fusion conditions and significant energy gain are discussed. Inertial fusion confinement time and ICF confinement parameter are defined. It is shown that the two basic ingredient of ICF, namely strong compression at low entropy, and hot spot ignition, just follow from the requirement of large gain. Power balance of an igniting plasma and ignition conditions are discussed. Conventional and advanced ignition schemes are outlined, While most of the presentation concerns deuterium-tritium fuels, conditions for, and potentials of, advanced fuel ICF are also briefly discussed.