{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"e6e3090979fd6fc47b8f285d1fae6f3c8ca7d485f5c3d132643794434ecb938f","created":"2026-10-03T07:18:08Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"377b55cc0b1b7c443fef828f4dab4be6a25396bf24a9a690c6c1fac3f5d9a91c","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"yes-no","assisted_by":[],"external_id":"plasma.qed-cascades.collective-pair-plasma","kind":"well-posed","literature_status":"open","n":"1","parents":[],"plain":"For the pairs from a cascade to act as a true plasma, they must be dense enough to respond together to fields. The question is whether existing lasers and electron beams can produce such a pair plasma and show its collective behavior.","posed_since":"","precise":"Pairs created by beam-laser or laser-laser cascades act collectively only if the relativistic pair plasma frequency exceeds the inverse interaction time; Qu, Meuren and Fisch (2021) predict a measurable blue shift of the laser frequency as a signature. Determine whether the frequency upshift, or another collective signature such as field screening or plasma-wave emission, can be measured with existing multi-PW lasers and 10 GeV-class electron beams, and give the expected magnitude and required detection resolution.","problem_ref":null,"references":"","settled_by":"An experiment measuring laser spectral upshift or another collective signature that scales with pair density as predicted.","status_note":"","title":"Laboratory pair plasma with measurable collective effects","topic_ref":"3d0d7926a3332ed1d5c98bce793a625e7064aa0a336ed90e374a074aaf4cfe04"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"5fa54c7ee23664ef84ba852bd8bb28ec921bd2f81b3594dda814fc900546fc7d","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"7d1abbe374b4a8343207fc228d5542ce60307311cd69b8353101a9d7a7574b3a","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"X4rB4uU5mvlxbe3Nu_ZOY21gOSVA5Gp0r8elFP4rVkKnMIWqmqyDcIEVXUErltQgHI8pIrv7JgKq1KY-VINrCA"},"schema":"pubphys.envelope/1"},"record_hash":"5fa54c7ee23664ef84ba852bd8bb28ec921bd2f81b3594dda814fc900546fc7d","leaf_index":1850}