Cryogenic Deuterium and Deuterium-Tritium Direct–Drive Implosions on Omega

Abstract

The success of ignition target designs in inertial confinement fusion (ICF) experiments critically depends on the ability to maintain the main fuel entropy at a low level while accelerating the shell to ignition-relevant velocities of V imp > 3 ×107 cm/s. The University of Rochester’s Laboratory for Laser Energetics has been implodingcryogenic deuterium and deuterium–tritium targets on the Omega Laser System for over a decade. Fuel entropy is inferred in these experiment by measuring fuel areal density near peak compression. Measured areal densities up to ⟨ρR⟩n ∼ 300 mg/cm2 (larger than 85 % of predicted values) are demonstrated in the cryogenic implosion with V imp approaching 3 ×107 cm/s and peak laser intensities of 8 ×1014 W/cm2. Scaled to the laser energies available at the National Ignition Facility, implosions, hydrodynamically equivalent to theseOmega designs, are predicted to achieve ⟨ρR⟩n > 1. 2 g/cm2, sufficient for ignition demonstration in direct-drive ICF experiments.