{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"6664beb5ee021b49b5e26c8f459933fe77413ac1edc7b3a321ed0c577be3320b","created":"2026-10-03T07:18:08Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"c6ee4cb5bc5b0be8655357c7c84bbfb5b9802755d3b930c91e6214fa907e2c18","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"yes-no","assisted_by":[],"external_id":"plasma.stellarator-optimization.qs-beta-stability","kind":"well-posed","literature_status":"partially-resolved","n":"1","parents":[],"plain":"Quasisymmetry is a hidden symmetry of the field strength that makes particles in a 3D stellarator move as if in a symmetric machine, and it has been achieved almost exactly in vacuum fields. Whether it can be kept while the plasma pressure is high enough for a reactor and the plasma stays stable is unknown.","posed_since":"","precise":"Quasisymmetry ($\\left|B\\right|$ depending on flux-surface angles only through one fixed linear combination) was achieved in vacuum with symmetry-breaking amplitude about 5e-5 of the field strength (about $0.5\\,\\mathrm{G}$ in a $1\\mathrm{e}4\\,\\mathrm{G}$ field; Landreman and Paul, 2022). Determine whether equilibria exist with quasisymmetry error below 1e-3, volume-averaged $\\beta$ of at least $5\\,\\mathrm{percent}$, ideal-MHD ballooning and kink stability, and nested flux surfaces, and map the trade-off frontier between these quantities. An answer is explicit configurations or a demonstrated frontier.","problem_ref":null,"references":"","settled_by":"Published equilibria verified by independent equilibrium and stability codes, or a systematic frontier showing incompatibility.","status_note":"Finite-$\\beta$ precisely quasisymmetric equilibria were reported after 2022; simultaneous stability at reactor $\\beta$ is not established.","title":"Precise quasisymmetry together with MHD stability at reactor pressure","topic_ref":"ea827242773f8b9fc91ff7ca2acb740fcd017fdea46fc2cbf3a53387d9b527bc"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"8f19874020f3124376226da8c9b84816697d2055d998e03fc7094418cf746c1e","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"070eeaa282757f390c5689e0e9605513b51fde23e66b77f682b211a5f29712d3","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"DpDn9N1KsEtCq_BePsa5m25wYrBRKCWN08YOyLFg67jiACdP9Yuss9wzZHsUKo1jBGOXnNBt5NnDRK6OPuZfAA"},"schema":"pubphys.envelope/1"},"record_hash":"8f19874020f3124376226da8c9b84816697d2055d998e03fc7094418cf746c1e","leaf_index":1871}