Pulsed-laser induced multiple recollisions dynamics in nonsequential double ionization of argon atom

Using the three-dimensional (3D) classical ensemble model, we investigate the multi-collision dynamics of argon under counter-rotating two-color circularly polarized (TCCP) laser fields. We find that not only the recollisioninduced ionization (RII) and recollision-induced excitation with subsequent ionization (RESI) mechanisms occur in the single-recollision (SR) and double-recollision (DR) events but also another alternating collision ionization process can take place. In the travel time distribution, both the second and fourth peaks, which indicate the return times of tunneling electrons, are missing at low laser intensity but occur at high laser intensity. This is due to the interplay between the ionization moment and the effect of Coulomb defocusing or focusing on the rescattering electron. Finally, we reveal the proportion of DR event decreases with increasing laser intensity and identify the energy transfer of second recollision increasing more dramatically than that of first recollision under high light intensity.