Low Fuel Convergence Path to Direct-Drive Fusion Ignition

A new class of inertial fusion capsules is presented that combines multishell targets with laser direct drive at low intensity (2.8×10¹⁴ W/cm²) to achieve robust ignition. The targets consist of three concentric, heavy, metal shells, enclosing a volume of tens of μg of liquid deuterium-tritium fuel. Ignition is designed to occur well "upstream" from stagnation, with minimal pusher deceleration to mitigate interface Rayleigh-Taylor growth. Laser intensities below thresholds for laser plasma instability and cross beam energy transfer facilitate high hydrodynamic efficiency (∼10%).