α-Decay in Ultra-Intense Laser Fields

We investigate the \alpha-decay of a spherical nucleus under the influence of an ultra-intense laser field for the case when the radius vector joining the center-of-masses of the \alpha-particle and the daughter is aligned with the direction of the external field. The time-independent part of the \alpha-daughter interaction is taken from elastic scattering compilations whereas the time-varying part describes the interaction between the decaying system with the laser field. The time-dependent Schr\"odinger equation is solved numerically by appealing to a modified scheme of the Crank-Nicolson type where an additional first-order time derivative appears compared to the field-free case. The tunneling probability of the \alpha-cluster, and derived quantities (decay rate, total flux) is determined for various laser intensities and frequencies for either continous waves or few-cycle pulses of envelope function F(t)=1. We show that in the latter case pulse sequences containing an odd number of half-cycles determine an enhancement of the tunneling probability compared to the field-free case and the continuous wave case. The present study is carried out taking as example the alpha decaying nucleus $^{106}$Te.