Fusion alpha particle momentum deposition in thermonuclear burn dynamics
File(s)
Published version
Author(s)
Type
Journal Article
Abstract
In inertial confinement fusion, the deuterium and tritium fusion alpha particles carry not only energy but also appreciable momentum that is typically neglected in models of thermonuclear burn. In the central hotspot ignition scheme, the hotspot must self-heat and propagate thermonuclear burn before disassembly. Using radiation–hydrodynamics simulations with a Monte Carlo alpha particle transport model, we investigate the effect of alpha momentum deposition across sub-ignition to robustly igniting regimes by hydrodynamic scaling of current central hotspot ignition designs from the National Ignition Facility (NIF). We find that the effective alpha particle ram pressure accelerates the shell at burn, reducing hotspot compression, increasing the rate of disassembly and decreasing yield. This causes a notable (∼30%) reduction in yield at current NIF scale, with a persistent (∼10%) penalty at larger hydrodynamic scales. These results demonstrate that alpha momentum deposition is a significant effect for present ignition-scale implosions, necessitating its inclusion in ignition criteria, burn models, and designs for high-gain inertial confinement fusion.
Date Issued
2026-05-01
Date Acceptance
2026-04-12
Citation
Physics of Plasmas, 2026, 33 (5)
ISSN
1070-664X
Publisher
AIP Publishing
Journal / Book Title
Physics of Plasmas
Volume
33
Issue
5
Copyright Statement
© 2026 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
License URL
Publication Status
Published
Article Number
050702
Date Publish Online
2026-05-05