2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/33677In this paper, we study by a functional method the vacuum instability of a charged scalar field, when it is quantized in the background of the Reissner-Nordtrom black hole; we also show that the first stage of the evaporation process of the black hole can be driven by a Schwinger-like effect.10 pages, no figure, accepted for publication in Physical review DGeneral Relativity and Quantum Cosmologytext