Displacement Current Density
$\text{Displacement Current Density}$ is the time rate of change of the $\textit{Electric Flux Density}$.
This is a measure of how quickly the electric field changes if we observe it as a function of time.
This is different than if we look at how the electric field changes spatially, that is, over a region of space for a fixed amount of time.
Applicable units are those of quantitykind:DisplacementCurrentDensity
http://www.iso.org/iso/home/store/catalogue_tc/catalogue_detail.htm?csnumber=31891
http://www.maxwells-equations.com/math/partial-electric-flux.php
http://dbpedia.org/resource/Electric_flux
$J_D = \frac{\partial D}{\partial t}$, where $D$ is electric flux density and $t$ is time.