Some classical electron trajectories in the gradient electric field, hitting the same point on the detector. The scaled energy ε = −0.1, the scaled electric field gradient α = 3.0, the detector is located at z = −0.5 plane. Different trajectories are represented by different types of lines. The given point on the detector is as follows: (a) ρ = 1.5, z = −0.5; (b) ρ = 1.0, z = −0.5.