{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"0b01dad6439e779a45086870585005a0a74ada888a83ba9ed8999d6bdc6b40bd","created":"2026-10-03T07:18:08Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"ec7229bf94111a4296ab777fcff98501388b6b9316638acd6668ac67b6784206","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"yes-no","assisted_by":[],"external_id":"plasma.qed-cascades.lab-avalanche-threshold","kind":"well-posed","literature_status":"open","n":"1","parents":[],"plain":"In colliding laser beams of enough intensity, the field itself should keep re-accelerating new pairs so their number grows exponentially. No laboratory has yet reached the needed intensity or seen this growth.","posed_since":"2008","precise":"In counterpropagating or multi-beam (dipole-wave) laser fields an avalanche cascade, with pair number growing as $\\exp(\\Gamma t)$ over several laser periods, is predicted above an intensity of order $1e31\\ \\mathrm{erg}\\ \\mathrm{s}^{-1}\\ \\mathrm{cm}^{-2}$ for 1-micron light, about ten times the record peak intensity of about $1e30\\ \\mathrm{erg}\\ \\mathrm{s}^{-1}\\ \\mathrm{cm}^{-2}$ (2021, approximate). Determine the minimal laser energy and geometry (colliding pulses, dipole focusing, single-pulse reflection from a plasma mirror) at which the pair number grows by several e-foldings, and observe it through positron yield scaling that exceeds the one-generation shower prediction.","problem_ref":null,"references":"","settled_by":"A positron-yield measurement versus intensity at a multi-10-PW facility showing exponential growth beyond seeded shower predictions.","status_note":"No laboratory avalanche cascade is known to this compilation as of 2026.","title":"First laboratory observation of a self-sustained avalanche QED cascade","topic_ref":"3d0d7926a3332ed1d5c98bce793a625e7064aa0a336ed90e374a074aaf4cfe04"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"3de8dad991414c538392d7daf5ca1ebf1c192ce235057d1d18d6c267127e4b5d","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"3e8d5fdcd89fff39ad1c48c4c9bd36d2c3a19fcb3a22e01d61978d8fb106e725","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"cPa2cE8ME2xJxGgkG8K3HW7c90_tYWnjaPUYVUXYuJRIB-Lj4weS1TTQQ_DKgbVV7Qy255eHAVD7sSjnM-RXDw"},"schema":"pubphys.envelope/1"},"record_hash":"3de8dad991414c538392d7daf5ca1ebf1c192ce235057d1d18d6c267127e4b5d","leaf_index":1852}