Abstracto
- Expressions for the complete metric and vector potential perturbations of solutions of the Einstein–Maxwell equations with a null background electromagnetic field in terms of two complex scalar potentials are derived using Wald’s method of adjoint operators. The perturbations of the Bell–Szekeres solution, in the regions prior to the collision of the plane‐fronted waves, are obtained by this approach. We find that there exist nontrivial u‐independent perturbations (where ∂u defines the direction of propagation of the colliding wave) which, when the electromagnetic perturbation vanishes, are exact solutions of the Einstein–Maxwell equations.