In
physics, the
electric displacement field, denoted by
D, is a
vector field that appears in
Maxwell's equations. It accounts for the effects of free and bound charge within materials. "
D" stands for "displacement", as in the related concept of
displacement current in
dielectrics. In
free space, the electric displacement field is equivalent to flux density, a concept that lends understanding to
Gauss's law. It has the
SI units of coulomb per squared metre (C m
-2).