  Recent attoclock experiments and theoretical studies regarding the
strong-field ionization of atoms by few-cycle infrared pulses revealed new
features that have attracted much attention. Here we investigate tunneling
ionization and the dynamics of the electron probability using Bohmian
Mechanics. We consider a one-dimensional problem to illustrate the underlying
mechanisms of the ionization process. It is revealed that in the major part of
the below-the-barrier ionization regime, in an intense and short infrared
pulse, the electron does not tunnel \through" the entire barrier, but rather
already starts from the classically forbidden region. Moreover, we highlight
the correspondence between the probability of locating the electron at a
particular initial position and its asymptotic momentum. Bohmian Mechanics also
provides a natural definition of mean tunneling time and exit position, taking
account of the time dependence of the barrier. Finally, we find that the
electron can exit the barrier with significant kinetic energy, thereby
corroborating the results of a recent study [Camus et al., Phys. Rev. Lett. 119
(2017) 023201].
