Mapping initial transverse momenta of tunnel-ionized electrons to rescattering double ionization in nondipole regimes.

We investigate the double ionization of a model Neon atom in strong middle infrared laser pulses by simulating the classical trajectories of the electron ensemble. After one electron tunnels out from the laser-dressed Coulomb barrier, it might undergo different returning trajectories depending on its initial transverse momentum, which in this wavelength may propagate along or deviate from the polarization direction. This initial transverse momentum determines the rescattering time, and thus some trajectories can have returning time longer than one optical cycle. These late-returning trajectories determine the correlated electron-electron momentum distribution for double ionization and allow us to disentangle each double ionization event from the final momentum distribution. The description of these trajectories allow us also to understand how the nondipole effects modify the correlated electron-electron momentum distribution in double ionization.