Discussion of paper by M. P. Nakada and G. D. Mead, ‘Diffusion of protons in the outer radiation belt’

Nakada and Mead [1965] have presented calculations of proton inward diffusion rates in the outer magnetosphere based on a diffusion mechanism originally proposed by Kellogg [1959] and applied in detail by Parker [1960] and by Davis and Chang [1962]. In their discussion of this mechanism, Nakada and Mead have presented a drawing (their Figure 1) that follows Parker's [1960] equation 20 and Davis and Chang's [1962] equation 13. These equations and consequently the figure are not correct and could lead to a misinterpretation of particle behavior. A corrected version of their drawing appears here as Figure 1.