Histograms of simulated path lengths of guiding center motion and full orbital motion for 25 MeV protons arriving promptly at radius r = 0.35 AU from the Sun, for computations described in Fig. 3 and in the text, in comparison with the average path length of magnetic field lines. The guiding center path length of promptly arriving particles (before the arrival of the backscattered population) is usually shorter than the average path length of magnetic field lines because of the finite radius of the gyromotion, which implies that the particle samples the magnetic field over a range of positions and need not exactly follow the random walk of individual field lines. The full orbit path length of the particles is longer because the gyromotion implies that particles follow a longer path than their guiding centers.