Scatter plot of electron density contrast (y-axis) against advected structure size (x-axis) . Uncertainties in electron density contrast are due to not knowing the variation of the alpha particle abundance within the structures. Background shading shows contours of Eq. (2) with r₀ = 0.3 AU, which gives the fractional change in intensity a white-light instrument at 1 AU would see when viewing the blobs. The fractional intensity change values assume zero velocity smear across the observing instrument.