Counts per day on Ulysses for particles of different sizes for the two models with (Z₀ = 1000 AU, model 1; solid lines) and without (Z₀ = 50 AU, model 2; dotted lines) the heliospheric interface. The different colors match particles of different sizes: a = 150 nm (red lines, β = 1.595), a = 250 nm (blue lines, β = 1.264), and a = 500 nm (green lines, β = 0.639). The black points are the Ulysses experimental counts.