GENERAL-RELATIVISTIC EFFECTS ON THE INDUCED ELECTRIC-FIELD EXTERIOR TO PULSARS

The importance of general relativity to the induced electric field exterior to pulsars has been investigated by assuming aligned vacuum and nonvacuum magnetosphere models. For this purpose, the stationary and axisymmetric vector potential in the Schwarzschild geometry has been considered and the corresponding expressions for the induced electric field due to the rotation of the magnetic dipole have been derived for both vacuum and non-vacuum conditions. Due to the change in the magnetic dipole field in curved spacetime, the induced electric field also changes its magnitude and direction and increases significantly near the surface of the star. As a consequence, the surface charge density, the acceleration of charged particles in vacuum magnetospheres, and the space charge density in nonvacuum magnetospheres greatly increase near the surface of the star. The results provide the most general feature of the important role played by gravitation and could have several potentially important implications for the production of high-energy radiation from pulsars.