Orbital variation of the CR proton flux along the Sun’s orbit, plotted against longitude (with Sun’s position at 90°). All curves are rescaled to an offset value of 1 for comparison. The black line and green crosses show the variation for an orbit at r = 7.9 kpc and z = 0 for 1 GeV and 100 GeV, respectively. The blue line and red boxes show the same energies for an orbit at r = 5 kpc. The left panel again shows the case of isotropic diffusion, while the right panel has ϵ = 0.01, and the variation is much more pronounced.