{"paper":{"title":"SPECTRE: A robust solver for 3D equilibria with arbitrary topology","license":"http://creativecommons.org/licenses/by/4.0/","headline":"","cross_cats":["physics.comp-ph"],"primary_cat":"physics.plasm-ph","authors_text":"A. Goodman, C. Lazzati, C. Smiet, E. Balkovic, E. Lanti, J. Geiger, J. Loizu, J. P. Graves, R. Ramasamy","submitted_at":"2026-07-29T17:06:07Z","abstract_excerpt":"We present SPECTRE, a new equilibrium code based on the Multi-Region relaxed MHD model for robustly calculating 3D equilibria with general magnetic topology, allowing for flux surfaces, magnetic islands, and chaos. The code builds on a previous MRxMHD solver, SPEC, but performs significantly better thanks to a new formulation of force, the use of a stable trust-region-based least squares minimization scheme, as well as several additional features. SPECTRE is verified through application to configurations with known equilibrium solutions, in vacuum and with finite beta, both in the fixed bounda"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2607.27135","kind":"arxiv","version":1},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2607.27135/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}