Fig. 1. Time evolution of laser field whose peak amplitude, central frequency, and duration are 0.1 a.u., 0.3747 a.u., and 20 optical cycles, respectively.

Fig. 2. Ionization process of electron irradiated by the laser pulse whose duration is 60 optical cycles. (a) Bohmian trajectories calculated by the BM and (b) probability density of the electron obtained by numerically solving the TDSE.

Fig. 3. Time evolution of (a) trajectory and (b) energy of the typical BP.

Fig. 4. (a) Time evolution of the total energy (solid black curve), and kinetic energy (dotted red curve) of BP, (b) the work done by the resultant force acting on BP (solid blue curve), and the increment of kinetic energy (dotted red curve).

Fig. 5. Work done by the resultant force (solid black curve) and its component forces, i.e., electric field force (dashed red curve), Coulomb force (dash-dotted blue curve), and quantum force (dotted magenta curve).

Fig. 6. Work done by the resultant forces (solid black curve) and its component forces, i.e., electric field force (dashed red curve), Coulomb force (dash-dotted blue curve), and quantum force (dotted magenta curve) (a) at excitation moment (from t = 96 a.u. to t = 107.8 a.u.) and (b) in the excitation-ionization process (from t = 166 a.u. to t = 300 a.u.).