Production of electron-positron pairs in a strong magnetic field and in a field of a plane eletromagnetic wave

Processes of electron-positron pair production by an external photon spreading normally to a magnetic field and to the direction of propagation of a plane circularly polarised electromagnetic wave, are treated within the framework of the Dirac hole theory. An external photon is taken into account for the perturbation theory, whereas the whole process is examined in the Dirac hole theory. On the basis of the exact solution of the Dirac equation governing the behaviour of charged particles in fields of a given configuration, formula for spectrum-angle distributions for pairs created in the interaction of an external photon with the ''l-photons'' of the wave have been derived. The probabilities of pair production by two photons (external photon plus wave photon) have been determined for all essential ranges of change of parameters. A detailed analysis has also been made of the single-quantum and two-quanta (1=0, +-1) processes of pair production for a wide range of change of the principal parameters, including the magnetic fields comparable to the critical magnetic field H approximately Hsub(0) = m2c2/en 4.4x1013Oe. Pair production by two photons in such a magnetic field and in the field of electromagnetic waves has been examined, in particular, for the case where one of the particles is created in a state with large quantum numbers. It is suggested that the process being considered may occur near pulsars