26th Australian Institute of Physics Congress and the Australian and New Zealand Conference on Optics and Photonics

Laser requirements for direct-drive inertial fusion energy

Not scheduled

20m

Belinda Hutchinson Building (The University of Sydney )

Contributed Oral ANZOS | Photonics and Optics (ANZCOP)

Speaker

Igor Morozov (Macquarie University, Australia)

Description

Inertial fusion energy (IFE) seeks to generate power through the repeated thermonuclear burn of small deuterium–tritium (DT) targets compressed and heated by intense, pulsed drivers. In laser-driven IFE, nanosecond pulses delivering megajoule-scale energy must ultimately operate at several shots per second with high wall-plug efficiency, precise pulse shaping, broad spectral bandwidth, excellent irradiation uniformity, and sufficient durability for power plant operation. Laser technologies proposed for IFE include frequency-converted diode-pumped solid-state lasers and various excimer lasers.

Although inertial confinement fusion energy breakeven has been experimentally demonstrated using an indirect-drive approach, this architecture is unlikely to provide a practical route to commercially viable IFE. Its inherently low laser-to-fuel coupling efficiency, combined with the extreme complexity of manufacturing precision hohlraum target assemblies, creates barriers that are difficult to reconcile with economic power production. Direct drive presents its own challenges, including stability, symmetry, and target-fabrication issues that require resolution. However, these appear to be engineering and physics problems to mitigate, rather than intrinsically prohibitive limitations.

In this report, we focus on the direct-drive implosions of relatively large DT targets that would allow one to increase the fuel burn fraction, ultimately reducing the target production costs per output energy unit. Optimised laser pulse shapes and target designs are presented depending on the available laser pulse energy. Optimisation has been done using radiation-hydrodynamics simulations.

Further reduction of a target cost could be achieved by using advanced fusion fuels that do not require low-temperature cryogenics and rely on a lower amount of expensive tritium. Ignition of such targets is shown to be challenging but possible with further development of the laser technologies. Technical and economical laser requirements for efficient and commercially reliable burning of pure DT and advanced fuels are discussed.

This research is funded by the ARC Linkage Grant No LP220100061.