Conceptual illustration of radio wave propagation from the star toward the planet. The star is shown with a simplified dipolar magnetic field, and its rotation axis is indicated by the upward arrow. Two emission cones are depicted: the cone closer to the star lies in regions of stronger magnetic field (strong B), while the outer cone is located in weaker fields (weak B). The background color represents the magnetic field strength (orange–red: strong; green–blue: weak). As radio waves propagate into regions of stronger field (inner cone), the refractive index decreases, leading to reflection at the iso-f_ce surface and a flattening of the cone on that side. The illustration is not shown to scale.