Mean electron density profiles for different SZA range in the terminator region. Panels a shows the averaged electron density profiles, with the solid, dashed, and dotted lines representing profiles of the |IMF| = 1 nT case, |IMF| = 3 nT case, and |IMF| = 5 nT case, respectively. Panel b shows the averaged electron density profiles for the |IMF| = 3 nT case. Here, the solid and dashed lines represent profiles of the northern and southern hemispheres. The profiles are shifted on the x-axis by the amounts marked in the figure.