The ISKRA-4 and ISKRA-5 lasers are lasers which were built by the Soviet Union at RFNC-VNIIEF in Arzamas-16 (Арзама́с-16) with the approximately 2 kJ output ISKRA-4 laser being completed in 1979 and the 30 kJ output ISKRA-5 laser which was completed in 1989. The main use for both lasers being the investigation into inertial confinement fusion, high energy density physics and nuclear weapons research. The Russian laser fusion program was first initiated on the suggestion of Andrei Sakharov in 1962 concerning the possibility that lasers may be capable of achieving the conditions for fusion in imploding spherically symmetrical fuel capsules.