  Hollow plasma channels are attractive for lepton acceleration because they
provide intrinsic emittance preservation regimes. However, beam breakup
instabilities dominate the dynamics. Here, we show that thin, warm hollow
channels can sustain large-amplitude plasma waves ready for high-quality
positron acceleration. We verify that the combination of warm electrons and
thin hollow channel enables positron focusing structures. Such focusing
wakefields unlock beam breakup damping mechanisms. We demonstrate that such
channels emerge self-consistently during the long-term plasma dynamics in the
blowout's regime aftermath, allowing for experimental demonstration.
