Self-seeded single-laser quantum electrodynamics cascades with a curved plasma mirror

We demonstrate a self-seeded quantum electrodynamics (QED) cascade driven by a single 100 PW laser pulse reflected from a curved plasma mirror. Three-dimensional particle-in-cell simulations show that the reflected field self-injects electrons from the mirror surface and accelerates them toward the geometric focus, where the intensity reaches a0 ≈ 4000, triggering an avalanche-type cascade with more than seven generations. The generated pairs are accelerated within a propagating wave rather than a standing wave, producing 60 nC of pairs in collimated beams with high contrast to background electrons. The generated pair plasma exhibits collective behavior, absorbing the incident laser power and screening the laser field at high intensities. This single-beam geometry eliminates multipulse alignment requirements and provides a direct path to studying prolific light-to-matter conversion in strong-field QED.