Laser-enhanced nuclear fusion in the multiphoton regime*

Quantum tunneling between fusing nuclei is considered in the presence of a sinusoidal time-varying

external field. The associated nonclassical equation of motion is treated using a Floquet/Volkov (FV)

analysis as well as a Kramers-Henneberger (KH) analysis, which are both compared against a first-

principles numerical solution of Crank-Nicolson (CN) type. Numerical validation of the FV formula

justifies its use in analytical estimates of laser-enhanced reaction rates, while the KH formula fails

to reproduce the predictions of the other methods. For a Deuterium–Tritium (DT) plasma at a

temperature of 1 keV, calculations suggest that significant enhancement of fusion reactivity requires

field strengths on the order of 10^15–10^16 V/m and photon energies on the order of 1 keV. The

enhancement effect is more sensitive to increases in field strength at lower photon energies.