The displacement D in a medium is equal to this quantity times the electric field, and for linear materials, the total energy stored in an electrostatic system is equal to this times one-half the integral over all space of the square of the electric field.
In plasmas above the highest resonant frequencies, this quantity is approximated by one minus the plasma frequency over the frequency of propagation. The assumption of causality connects the real and imaginary parts of this frequency-dependent quantity according to the Kramers-Kronig formalism, and it is related to the molar polarizability by the Clausius-Mossotti equation. The displacement D in a medium is equal to this quantity times the electric field, and for linear materials, the total energy stored in an electrostatic system is equal to this times one-half the integral over all space of the square of the electric field. A capacitor can store additional charge by inserting a dielectric to change this quantity. For 10 points, identify this quantity symbolized epsilon which quantifies the effect of an electric field on a medium.
In plasmas above the highest resonant frequencies, this quantity is approximated by one minus the plasma frequency over the frequency of propagation.
electric permittivity (accept relative permittivity or the dielectric constant or elecric susceptibility before "electric field")