Extended Electrodynamics: II. Properties and invariant characteristics of the non-linear vacuum solutions

This paper aims to consider the general properties of the non-linear solutions to the vacuum equations of Extended Electrodynamics. The *-invariance and the conformal invariance of the equations are mentioned. It is also proved that all non-linear solutions have zero invariants: F_{\mu\nu}F^{\mu\nu} = (*F)_{\mu\nu}F^{\mu\nu} = 0. The three invariant characteristics of the non-linear solutions: amplitude, phase and scale factor are introdiced and discussed.