  Plasma-based positron acceleration is still an open question, as the most
efficient regimes for electron acceleration (quasi-linear and blowout) are not
directly applicable to positrons. Nevertheless, positron acceleration is a
stepping stone on the path toward a plasma-based lepton collider. In this work,
we propose a scheme for positron acceleration based on the spatial overlap of a
driver (electron or laser) beam and a positron beam, also known as a fireball
beam. Under appropriate conditions, these beams can self-consistently evolve
toward a hollow driver and focused positron beam on-axis, driving plasma waves
suitable for positron acceleration. This evolution seems to be a manifestation
of the current filamentation instability. We discuss how the self-consistent
dynamics affect the beam quality and perform a preliminary tolerance study.
