Reference number of sparks, N₀, under different assumptions of the geometry angles and the degree of aliasing, n. N₀ was obtained by fitting Eq. (9) to a single pulse stack with high S/N in session L99010. The left and right panels show N₀ for the outside and inside traverse geometry branches. For each of the three values of R_PA, namely − 3.4, − 2.9, and − 2.4°/°, a set of trial ρ_{1 GHz} between 2° and 8° was used. For clarity, the points for different ρ₀ are plotted with the horizontal offset proportional to ρ₀ − 4.5°. Although the carousel model prescribes the integer number of sparks, N₀ was not fixed to an integer value during the fit.