Principle and critical issues of laser fusion

Principle and critical issues of inertial confinement fusion (ICF) are briefly described. For ICF to work as energy production system, the achievement of high gain is required. Drivers such as lasers and particle beams are used to implode target capsules so that the compressed core is structured with a low density, high temperature spark and a high density, low temperature main fuels. We discuss the ignition condition of the spark. After discussing the coupling efficiency in the laser ablative acceleration of shell targets, a typical implosion dynamics is explained for a case of the high gain target, where a tailored laser pulse is required to produce the structure core. An importance of implosion stability and uniformity is described. Two different approaches of ICF, direct drive and in-direct drive, are explained with discussing their merits and demerits. Finally, physics subjects to be studied are explained, emphasizing the importance of implosion stability and energy transport. The importance of demonstration of the spark formation with a precision laser system is emphasized as the most critical issues to be demonstrated out in the next step of ICF research. (author)