  We theoretically study frustrated double ionization (FDI) of atoms subjected
to intense circularly polarized laser pulses using a three-dimensional
classical model. We find a novel "knee" structure of FDI probability as a
function of intensity, which is similar to the intensity dependence of
nonsequential double ionization probability. The observation of FDI is more
favourable when using targets with low ionization potentials and short driving
laser wavelengths. This is attributed to the crucial role of recollision
therein, which can be experimentally inferred from the photoelectron momentum
distribution generated by FDI. This work provides novel physical insights into
FDI dynamics with circular polarization.

Atomic Physics