What a foundation model breaks on plasma
May 2026
Polymathic's Walrus is a 1.3B-parameter foundation model trained across 19 physics scenarios including MHD. Zero-shot on plasma turbulence: one-step prediction is excellent, but autoregressive rollout exhibits a structural basin instability in the perpendicular magnetic plane. FP64-confirmed structural, not numerical. The published headline doesn't tell you any of this.