Indirect-direct hybrid-drive work-dominated hotspot ignition for inertial confinement fusion

TL;DR

This paper proposes a novel hybrid-drive scheme for inertial confinement fusion that combines indirect and direct laser drives to achieve work-dominated hotspot ignition, significantly improving stability and yield.

Contribution

It introduces a new hybrid-drive approach with enhanced shock and compression techniques that suppress instabilities and increase fusion yield.

Findings

Fusion yield of 15 MJ achieved with 1.32 MJ laser energy.

Suppression of hydrodynamic instabilities and asymmetry.

Hotspot ignition driven by work-dominated compression with high implosion velocity.

Abstract

An indirect-direct hybrid-drive work-dominated hotspot ignition scheme for inertial confinement fusion is proposed: a layered fuel capsule inside a spherical hohlraum with an octahedral symmetry is compressed first by indirect-drive soft-x rays (radiation) and then by direct-drive lasers in last pulse duration. In this scheme, an enhanced shock and a follow-up compression wave for ignition with pressure far greater than the radiation ablation pressure are driven by the direct-drive lasers, and provide large pdV work to the hotspot to perform the work-dominated ignition. The numerical simulations show that the enhanced shock stops the reflections of indirect-drive shock at the main fuel-hotspot interface, and therefore significantly suppresses the hydrodynamic instabilities and asymmetry. Based on the indirect-drive implosion dynamics the hotspot is further compressed and heated by the enhanced shock and follow-up compression wave, resulting in the work-dominated hotspot ignition and burn with a maximal implosion velocity of ~400 km/s and a lower convergence ratio of ~25. The fusion yield of 15 MJ using total laser energy of 1.32 MJ is achieved.