Physical parameters of the EP as a function of projected distance from the solar disk center, calculated at 32 selected points along its northern leg. Top panels: Observational values before subtraction of the D₃ contribution: Stokes I (left) and ratio Q/I (right). Bottom: Column density after subtracting the helium D₃ contribution (left based on the zero-magnetic field case from Heinzel et al. 2023) and the integrated intensity emitted in the Lα line (right).