학술논문
Demonstration of hot-spot fuel gain exceeding unity in direct-drive inertial confinement fusion implosions
Document Type
Article
Author
Williams, C. A.; Betti, R.; Gopalaswamy, V.; Knauer, J. P.; Forrest, C. J.; Lees, A.; Ejaz, R.; Farmakis, P. S.; Cao, D.; Radha, P. B.; Anderson, K. S.; Regan, S. P.; Glebov, V. Yu; Shah, R. C.; Stoeckl, C.; Ivancic, S.; Churnetski, K.; Janezic, R. T.; Fella, C.; Rosenberg, M. J.; Bonino, M. J.; Harding, D. R.; Shmayda, W. T.; Carroll-Nellenback, J.; Hu, S. X.; Epstein, R.; Collins, T. J. B.; Thomas, C. A.; Igumenshchev, I. V.; Goncharov, V. N.; Theobald, W.; Woo, K. M.; Marozas, J. A.; Bauer, K. A.; Sampat, S.; Waxer, L. J.; Turnbull, D.; Heuer, P. V.; McClow, H.; Ceurvorst, L.; Scullin, W.; Edgell, D. H.; Koch, M.; Bredesen, D.; Johnson, M. Gatu; Frenje, J. A.; Petrasso, R. D.; Shuldberg, C.; Farrell, M.; Murray, J.; Guzman, D.; Serrato, B.; Morse, S. F. B.; Labuzeta, M.; Deeney, C.; Campbell, E. M.
Source
Nature Physics; 20240101, Issue: Preprints p1-7, 7p
Subject
Language
ISSN
17452473; 17452481
Abstract
Irradiating a small capsule containing deuterium and tritium fuel directly with intense laser light causes it to implode, which creates a plasma hot enough to initiate fusion reactions between the fuel nuclei. Here we report on such laser direct-drive experiments and observe that the fusion reactions produce more energy than the amount of energy in the central so-called hot-spot plasma. This condition is identified as having a hot-spot fuel gain greater than unity. A hot-spot fuel gain of around four was previously accomplished at the National Ignition Facility in indirect-drive inertial confinement fusion experiments where the capsule is irradiated by X-rays. In that case, up to 1.9 MJ of laser energy was used, but in contrast, our experiments on the OMEGA laser system require as little as 28 kJ. As the hot-spot fuel gain is predicted to grow with laser energy and target size, our work establishes the direct-drive approach to inertial fusion as a promising path towards burning and ignited plasmas in the laboratory. Additionally, we report a record (direct-drive) fusion yield of 0.9 kJ on OMEGA, which we achieved with thin-ice deuterium–tritium liner targets.