Transition rate dependence on the improved turning point in ADK-theory

Abstract

Estimation of transition rate of ionization of atoms for short range potential, based on assumptions of Keldysh approximation, shows that short-range potential does not affect the energy of the final state of ejected electron, when it leaves the atom. Coulomb potential is then treated as perturbation of final state energy leading to the ADK-theory. But Coulomb interaction was not originally included in calculating the turning point. This we corrected in [1], though only for fields with intensities below those of the atomic field. But as the ADK-theory was recently extended to the case of superstrong fields, our calculations now include extension of potential range up to 1017 W/cm2; this leads to the shift of position of the turning point τ , which then influences transition rates for atoms in the low-frequency electromagnetic field of superstrong lasers. On Figs. 1 and 2 obtained from our calculations the value of Z was switched from 1 to 10 at field intensity of 5 × 1013 W/cm2 (atomic unit system), which is done for the first time ever. The second figure also indicates an enormous activity at fields 1013 W/cm2, which is due to strong tunneling effect for this energies of laser field. After that, there is saturation at a very low level of transition rate for fields from 1015 W/cm2 to 1017 W/cm2.