Dynamically assisted nuclear fusion

Abstract

We consider the prototypical deuterium-tritium fusion reaction. At intermediate initial kinetic energies (in the keV regime), a major bottle-neck of this reaction is the Coulomb barrier between the nuclei, which is overcome by tunneling. Here, we study whether the tunneling probability can be enhanced by an additional electromagnetic field, such as an x-ray free electron laser (XFEL). We find that this dynamical assistance should be feasible with present-day or near future technology.

Enhanced Fusion Mechanisms Towards Synthesizing Superheavy Elements

“…The resulting probability will enhance as the WKb S 1 decreases. The wavelengths of XFEL are ≥ 50pm, which are much larger than the associated wavelengths of the initial kinetic energies estimated (that are around 1.4 pm and 140 fm ), so the vector potential can be approximated by a purely time dependent field A(t) [1]. The center-of-mass motion decouples from the relative coordinate r − = r D − r T , with a dynamics governed by,…”

“…Quantum-mechanical tunneling allows the protons to go through the Coulomb barrier with a probability that is much larger than this, though still exponentially suppressed. Radiating with an intense electromagnetic field will deform the potential barrier and thus enhance or suppress tunneling [1].…”

“…This is called the Floquet approach. A more involved WKB scheme is presented [1], employing an ansatz ψ = Ce iS we find an equation for S(t, r), the eikonal equation, which can be separated into a zeroth order term S 0 (t, r) for the static tunneling and corrections S 1 (t, r) induced by the electromagnetic field. The tunneling assistance is highly dependent of the pulse profile in time.…”

“…Following [1], we split into a static and non-static solutions S 0 and S 1 respectively, after linearizing in A and S 1 leads to the set of equations,…”

“…where ∂ t S 0 = −ε. The above system varies with respect to [1] in the extra term due to the spatial dependence of the pulse.…”