Nonlinear collective effects in photon-photon and photon-plasma interactions

We consider strong-field effects in laboratory and astrophysical plasmas and high intensity laser and cavity systems. Current state-of-the-art laser facilities are close to reaching energy scales at which quantum electrodynamics will play a crucial role in the dynamics of plasmas and indeed the vacuum itself. Developments such as the free electron laser may also give a means for exploring remote violent events such as supernovae in a laboratory environment. Here we describe the implications of collective interactions between photons and photon-plasma systems. We give an overview of strong field vacuum effects and a set of equations describing the nonlinear propagation of an electromagnetic pulse on a radiation-plasma is derived. Effects introduced by QED in pair plasmas is described. Applications to laser-plasma systems and astrophysical environments are discussed.