Scatter plot of 2sin (Δθ/2) vs. Δ B/ B, which are equal if the magnetic field vector undergoes a pure rotation between measurements. Also shown, in the inset, is the pdf of the normalized difference χ = |Δ B/ B − 2sin (Δθ/2)|/(Δ B/ B), which is strongly peaked at zero. These plots show that the magnetic field in the solar wind tends to rotate between the measurements rather than change in strength.