Fundamental Studies on One-Dimensional Cannonball Targets at 10.6 µm Laser Wavelength

A new scheme for the inertial confinment fusion (ICF) pellet, called a Cannonball target, has been investigated experimentally using a 10.6 µm laser. The fuel pellet is surrounded by a tamper with a vacuum between the two, and the laser energy is introduced into this space through a small hole in the tamper. The fundamental properties of the Cannon-ball target, such as its absorption and hydrodynamics, and the emission spectra of ions and electrons, have been investigated. The results show a good absorption of 50% and a high hydrodynamic efficiency of 16%. It was found possible to suppress hot-electron preheating.