Fig. 16.

Summary of Van Allen Probe conjunctions when the inter-Probe separation was less than $0.2R_E$. (a) The $L$ value of Probe-A during each conjunction, plotted versus time with MLT on the color scale. There were 53 clusters of conjunctions during the time interval displayed that encompassed $\sim 24$ d of total observing time. The duration of each conjunction cluster was on the order of a few days. The increase in conjunction-cluster frequency and the decrease in $L$-coverage with time is an orbital effect (see text). (b) Histograms of the inter-Probe separations in $L$ during each cluster, normalized by the maximum value in each cluster. (c) Same as (b), but for MLT. (d) The location of Probe-A in $L$ and MLT during each conjunction with $B/B_{eq}$ plotted on the color scale (values greater than 1.1 are shown in grey)