A new type of photoinduced nuclear reactions is considered when a photon is absorbed by a continuum state and accompanied by nuclear rearrangement. An important example of such reactions is d+t+γ→α+n which, in the regions of space containing a hot d−t mixture and a very large number of low-energy photons, can dominate the d+t→α+n fusion reaction, leading to an additional high-energy release. The present estimates of the environmental conditions where this might happen are made based on first-order perturbation theory with several values of the infrared cutoff. It is shown that with a cutoff of 1 eV, which corresponds to infrared light, the photon capture is several times larger than the d−t fusion rate in the big bang nucleosynthesis in the early universe, makes a noticeable contribution to energy release in tokamaks, and dominates by a few orders of magnitude in laser-direct-driven inertial confinement fusion. No effect on these three environments can be seen if the infrared cutoff is 1 keV. However, with this cutoff the photon absorption in a d−t mixture could become noticeable in future laser facilities at power intensities above 1018Watt/cm2. With further increase of the intensity towards 1027Watt/cm2 photon capture will dominate even if the first-order perturbation theory breaks down at very large values of the infrared cutoff, around 1 MeV. The development of a nonperturbative approach to d+t+γ→α+n reaction is crucial to capture correctly the physics of low-energy photoabsorption with high-energy release.
Published by the American Physical Society
2024
