Time dependence of the average angular distance |Δ_θ| between the simulated perpendicularity condition and the observed IBEX ribbon. The results are shown for the solar-cycle (SC – blue line) and the LISM-fluctuation (LF – orange line) effects. The average angular distance |Δ_θ| is computed using the locations of the simulated condition in the sky computed at a constant radial distance of 50 AU from the HP (HP2 definition is used here), as inferred from Fig. 6.