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

TL;DR

This paper proposes a novel direct-drive amplifier scheme for 10 MJ laser-driven inertial fusion energy, enabling extended burn stages, higher gain, and relaxed engineering constraints, with potential for clean fusion energy.

Contribution

It introduces a new amplifier design that extends burn duration and achieves high gain at low convergence ratios, facilitating innovative target designs for fusion energy.

Findings

Fireball lasts for 30 ps with 330 g/cc density

Achieves 350 keV energy and 54 Tbar pressure at center

Enables relaxed hot spot and engineering requirements

Abstract

The National Ignition Facility successfully achieved target gain 2.4 thus marginally entering into burn stage.Meanwhile, a recent conceptual design on 10 MJ laser driver [Matter Radiat. Extremes 9, 043002 (2024)] provides a new room for exploring novel target designs and interesting phenomena in a burning plasma after ignition. In this paper, we propose an amplifier scheme with extended burn stage, which includes secondary implosion, generates extremely hot and dense fusion fireball, and produces additional gain. The amplifier scheme can be realized either by direct-drive or by indirect-drive. Here, we present a direct-drive amplifier design. The amplifier scheme can be realized at a low convergence ratio, so it can greatly relax the \r{ho} RT hot spot condition and the stringent requirements on engineering issues by a high gain fusion. Especially, the fireball lasts for 30 ps, reaching 330 g/cc, 350 keV, 54 Tbar at center when the secondary explosion happens, which leaves an important room for novel target designs towards clean fusion energy.