Abstract

A key requirement for the direct-drive laser-driven approach to inertial confinement fusion is the achievement of nearly perfect on-target irradiation uniformity. To achieve radial convergence ratios in excess of 25, drive nonuniformities must be kept below the level of ± 1 to 2%.¹ Thermal smoothing in the plasma atmosphere surrounding the target can be effective in reducing small-scale nonuniformities in the laser irradiation pattern.² At early times during an implosion, however, the plasma scale-lengths are short and the smoothing is insufficient to create the required level of drive uniformity. The intrinsic coherence of high-power lasers is one of the principal factors contributing to this problem.

© 1991 Optical Society of America