The photoionization microscopy of the hydrogen atom in a gradient electric field, with scaled energy ε = −0.1, scaled electric field gradient α = 3.0, and the detector located at z = −0.5 plane. (a) The dependence of the impact position ρ at the detector plane on the initial outgoing angle θ; (b) the two-dimensional electron probability density distribution on the detector plane, corresponding to the contribution of the total electron trajectories; (b) the electron probability density caused by the direct electron trajectories; (c) the electron probability density caused by the indirect electron trajectories; (e) the three-dimensional electron probability density distribution on the detector plane; (f) the image of Fig. 4(e).