On the weak-field limit of Pleba\'nski class electrodynamics

TL;DR

This paper develops a weak field approximation method for Plebański's nonlinear electrodynamics, enabling calculation of post-Maxwellian corrections and exploring conditions under which Maxwell's equations are approximately valid.

Contribution

It introduces a systematic weak field approximation for Plebański's class, allowing for order-by-order solutions and analysis of post-Maxwellian effects in nonlinear electrodynamics.

Findings

Derived a series of linear equations for weak fields

Identified conditions for Maxwell's equations to hold approximately

Discussed potential experimental tests of nonlinear effects

Abstract

Pleba\'nski's class of nonlinear vacuum electrodynamics is considered which is for several reasons of interest at the present time. In particular the question is answered under which circumstances Maxwell's original field equations are recovered approximately and which post-Maxwellian effects could arrise. To this end a weak field approximation method is developed allowing to calculate post-Maxwellian corrections up to Nth order. In some respect this is analogue of determining "post-newtonian" corrections from relativistic mechanics by a low velocity approximation. As a result we got a series of linear field equations which can be solved order by order. In this context the solutions of the lower orders occur as source terms inside the higher order field equations and represent a "post-Maxwellian" self-interaction of the electromagnetic field which increases order by order. One has to decide between problems with and without external source-terms, because without also high frequency solutions can be approximately described by Maxwell's original equations. The higher order approximations which describe "post-Maxwellian" effects can give rise for experimental tests of Pleba\'nksi's class. Finally two boundary value problems are discussed to have examples at hand.