We give the general results for spontaneous and photon-induced pair production in strong, constant parallel electric and magnetic fields. For photons propagating exactly parallel to the constant fields there is no effect. For photons propagating at right angles to the constant fields the vacuum behaves in a birefringent manner. These results generalize earlier work in the field by others who did not include a constant electric field. Some numerical estimates are given for both the spontaneous and photon-induced pair production rates using numbers currently thought to obtain near the surface of a pulsar-which is believed to possess not only a strong magnetic field but also a strong electric field.

• Received 19 January 1976

DOI:https://doi.org/10.1103/PhysRevD.14.340