Vacuum nonlinear electrodynamics curvature of photon trajectories in pulsars and magnetars

Near a magnetic neutron star electromagnetic emission should undergo nonlinear electrodynamic effects in strong magnetic fields. Manifestations of this effect in detected hard emission from magnetic neutron stars are discussed on the base of nonlinear generalizations of the Maxwell equation in vacuum. The dispersion equations for electromagnetic waves propagating in the magnetic dipole field were obtained in the framework of these theories.