Electron vortices in the amplitude of the atomic ionization by a few-cycle circularly polarized laser pulse

Electron vortices emerging in the amplitude of the ionization of an atom by an isolated few-cycle, circularly polarized electromagnetic pulse are analyzed in the multiphoton regime. We demonstrate that the number of vortices, as well as their position and strength, are determined by the relative magnitudes of the dynamical amplitude parameters corresponding to sequential photon absorption. It is shown that the phase maps of the ionization amplitude in the momentum space exhibit spiral structures, which are signatures of the Coulomb scattering phases.