Three-dimensional classical ensembles are employed to study recollision dynamics in double ionization of atoms by 780-nm intense lasers. After recollision one electron typically remains bound to the atom for a portion of a laser cycle, during which time the nucleus strongly influences its direction of motion. The electron then escapes over a suppressed barrier, with its final momentum depending critically on the laser phase at escape. The other electron remains unbound after collision, and typically drifts out in a momentum hemisphere opposite from its motion just after the collision. Several example trajectories at intensity 0.4 PW/cm2 with various time delays between recollision and ionization are presented.
Haan, Stanley L.; Breen, L.; Karim, A.; and Eberly, Joseph H., "Recollision dynamics and time delay in strong-field double ionization" (2007). University Faculty Publications and Creative Works. 487.