A light scattering approach on a micellar solution formed by a PS-PEO diblock copolymer was used to investigate the charge fluctuations of the solvent, a room temperature ionic liquid. The results suggest a pairwise potential model for the intermicellar interactions consisting of a hard sphere core and a repulsive Yukawa tail. The screening length is consistent with the nanometric scale of the charge fluctuations of the solvent, as estimated by recent theoretical works on the fluid structure of a molten salt in proximity of a charged surface.