  On 22 October 2015, VAP and MMS obtained near-continuous observations of the
full radial extent of the duskside equatorial plasmasphere and plume. The plume
is evident in in situ plasma data and an equatorial mapping of the ionospheric
total electron content. The properties of the equatorial plasmasphere change
dramatically from its the inner radiation belt to its outermost boundary (the
magnetopause, near a reconnection site). The density decreases by a factor of
$\sim$1000 over this range and scales with $L$-shell as $L^{-4.3\pm0.4}$, in
good agreement with with theoretical expectations of the expansion of a flux
tube volume during outward radial transport. The proton temperature increases
by a factor of $\sim$100 over this same range, with the most pronounced heating
occurring at $L>7$, which was covered by the orbit of MMS.
