Suppression of pair beam instabilities in a laboratory analogue of blazar pair cascades

Proceedings of the National Academy of Sciences, Volume 122, Issue 45, November 2025. SignificanceIn this work, a dense beam of electron–positron pairs is produced using protons accelerated by the Super Proton Synchrotron at CERN. The beam is propagated through an ambient plasma, analogous to pair cascades produced as blazar jets propagate …