Top panels show the magnetic-field components, magnetic-field magnitude (left y-axis), and bulk solar-wind speed (right y-axis) for a representative switchback interval (left) and nonswitchback interval (right). Bottom panels show the normalized histogram of the magnetic-field angle ϕ for the same intervals. The black vertical line marks ϕ₀, the angle of the mean magnetic field B_0and the red vertical line marks the angle of the most probable magnetic-field direction, B_m. The magenta vertical lines indicate ϕ_a and ϕ_b, which define the angular extent of the dominant distribution around ϕ₀.