Internal structure of charged black holes

We investigate the internal structure of charged black holes with a spherically symmetric model in the double-null coordinate system. Hawking radiation is considered using the S-wave approximation of semiclassical backreaction and discharge is simulated by supplying an oppositely charged matter to the black hole. In the stage of formation, the internal structure is determined by the mass and charge of collapsing matter. When the charge-mass ratio is small, a wormhole-like internal structure is observed. The structure becomes analogous to the static limit as the ratio reaches unity. After the formation, mass inflation induces large curvature in the internal structure, which makes the structure insensitive to the late-time perturbations. The internal structure determined from the formation seems to be maintained during a substantial mass reduction. The discharge and neutralization of charged black holes is also investigated for both nonevaporating and evaporating cases. Finally, we discuss the implications of the wormhole-like structure inside of charged black holes.