Simulated NWC electron precipitation structures after subtraction of initial flux distribution from final flux distribution. Parameters used in simulation: frequency ω/(2π) = 19.8 kHz; wave amplitude δb = 200 pT; semiband width 500 Hz; and N₀ = 1000 counts/s. The equatorial pitch angles α_eq used in the simulation ranging from 0.3 to 0.44, corresponding to the observation range by the DEMETER and NOAA satellites. The loss cones were set as follows: LC_drift = (a) 5°; (b) 10°; (c) 15°, all of which were with a bounce loss cone.