Tidal Forces in Reissner-Nordstr\"om Spacetimes
  We analyze the tidal forces produced in the spacetime of Reissner-Nordstr\"om black holes. We point out that the radial component of the tidal force changes sign just outside the event horizon if the charge-to-mass ratio is close to $1$ unlike in Schwarzschild spacetime of uncharged black holes, and that the angular component changes sign between the outer and inner horizons. We solve the geodesic deviation equations for radially falling bodies towards the charged black hole. We find, for example, that the radial component of the geodesic deviation vector starts decreasing inside the event horizon unlike in the Schwarzschild case. 
Lu\'is C. B. Crispino, Atsushi Higuchi, Leandro A. Oliveira, and   Ednilton S. de Oliveira
gr-qc