Amplifier scheme: driven by indirect-drive under 10 MJ laser toward inertial fusion energy

TL;DR

This paper proposes a novel amplifier scheme driven by a 10 MJ laser for inertial fusion energy, significantly increasing burn efficiency to 48% and relaxing ignition requirements.

Contribution

It introduces a new amplifier design utilizing cascading explosions in ICF, achieving higher burn efficiency at lower convergence ratios.

Findings

Burn efficiency increased to 48% in the proposed scheme.

Achieved gain of 33 at a convergence ratio of 24.

Scheme applicable to both indirect and direct drive methods.

Abstract

Burn efficiency is a key for commercial feasibility of fusion power station for inertial fusion energy, while burn efficiency is usually lower than 30% in the central ignition scheme of inertial confinement fusion (ICF). A recent conceptual design for a 10 MJ laser driver [Z. Sui and K. Lan et al., Matter Radiat. Extremes 9, 043002 (2024)] provides a new room for target design to achieve a higher burn efficiency. Here, we take the advantage of fuel density in reaction rate and propose a novel amplifier scheme for increasing burn efficiency via two cascading explosions by ICF. The amplifier scheme can be realized either by indirect-drive or by direct-drive. Here, we give a 1D design for an indirect-driven amplifier capsule containing 2.02 mg DT fuel under a 300 eV radiation generated by a 10 MJ and 1785 TW laser inside an octahedral spherical hohlraum. As a result, the amplifier capsule has a burn efficiency of 48% and a gain of 33 at a convergence ratio of 24. This novel scheme can achieve a relatively high burn efficiency at a relatively low convergence ratio, which can greatly relax the stringent requirements of high gain fusion on hot spot ignition conditions and engineering issues.