{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.topic/1","content_sha256":"3d5d56a293f831ad45031250f7fd5e1d9fe0b3012da82276ce6e8cae50ced8fb","created":"2026-10-03T07:17:52Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":[],"salt":"3acf77e4bb0fc66aff68a553cbe39fd12290d4c6669876d288e077cf95b8e435","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"topic"},"content":{"external_id":"plasma.tokamak-confinement","field":"plasma","n":"1","review_cite":"F. Wagner, A quarter-century of H-mode studies, Plasma Physics and Controlled Fusion, 2007","review_link":"https://doi.org/10.1088/0741-3335/49/12B/S01","review_verified":"true","summary":"Heat leaks out of a tokamak (a doughnut-shaped magnetic bottle for fusion fuel) mainly through small turbulent eddies. Above a threshold heating power the edge turbulence suddenly drops and an insulating layer forms (H-mode), but what triggers this, how dense the plasma may become and how the fuel mass changes the heat leakage are not understood.","title":"Tokamak turbulence, L-H transition and density limit","topic_ref":null,"why":"Confinement quality and the density limit set the size, cost and fusion power of a tokamak power plant."},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"06a56c8a16b24bd8d093b16cb10c927fc7bcbeff7471e51e9543e334992b233a","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"8ff6f774f0da52909ac95e70566cb6a4d1e8f81ef9bbe3935938661e5fc19b83","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"BXCHGmJDUKsT9tdyLnB0EsE2XTLydf99Zr3kshjk4pBZqePQEiDGMlz7dYepmWWuBEe2ISlIxv_vTsPigIxEAQ"},"schema":"pubphys.envelope/1"},"record_hash":"06a56c8a16b24bd8d093b16cb10c927fc7bcbeff7471e51e9543e334992b233a","leaf_index":308}