Enhanced proton-boron nuclear fusion cross sections in intense high-frequency laser

TL;DR

This paper demonstrates that intense high-frequency laser fields can significantly enhance proton-boron fusion cross sections by modifying the Coulomb barrier, with potential resonance effects at specific energies.

Contribution

It introduces a theoretical framework using Kramers-Henneberger transformation and WKB approximation to quantify laser-induced enhancement of fusion cross sections, revealing a dependence on a dimensionless parameter.

Findings

Fusion cross sections can be increased up to 26 times at certain energies.

Resonance peaks are shifted to lower energies under intense laser fields.

The enhancement depends on the ratio of quiver amplitude to nuclear contact radius.

Abstract

We investigate the proton-boron nuclear fusion cross sections under the influence of the intense linearly polarized monochromatic laser fields with high frequency. First, we rewrite the time-dependent Schr\"{o}dinger equation using Kramers-Henneberger (KH) transformation which allows for shifting all time dependence of the problem into the potential function. Then, for the intense laser fields that satisfy the high frequency limit, the time-averaged scheme in the KH framework should be valid. We can use WKB approximation to evaluate Coulomb barrier penetrability and then calculate proton-boron nuclear fusion cross sections by a phenomenological Gamow form. We show that the corresponding Coulomb barrier penetrability increases significantly due to the depression of the time-averaged potential barrier. As a result, we find that proton-boron nuclear fusion cross sections can be enhanced effectively depending on a dimensionless quantity $n_{\mathrm{d}}$, which equals the ratio of the quiver oscillation amplitude to the geometrical touching radius of the proton and boron nucleus. For $n_{\mathrm{d}}=9$, we predict that the resonance peak of the fusion cross-section is enhanced by about $26$ times at the incident energy of $\varepsilon=148$ keV. And for another incident energy of $\varepsilon=586$ keV, the resonance peak of fusion cross-section is not only enhanced but also shifted to lower energy of $\varepsilon=392$ keV due to the mechanism of over-barrier fusion.