{"ID":2840551,"CreatedAt":"2026-06-01T04:54:23.091178241Z","UpdatedAt":"2026-06-01T04:54:23.091178241Z","DeletedAt":null,"paper_url":"https://arxiv.org/abs/2511.13262","arxiv_id":"2511.13262","title":"Case study of a differentiable heterogeneous multiphysics solver for a nuclear fusion application","abstract":"This work presents a case study of a heterogeneous multiphysics solver from the nuclear fusion domain. At the macroscopic scale, an auto-differentiable ODE solver in JAX computes the evolution of the pulsed power circuit and bulk plasma parameters for a compressing Z Pinch. The ODE solver requires a closure for the impedance of the plasma load obtained via root-finding at every timestep, which we solve efficiently using gradient-based Newton iteration. However, incorporating non-differentiable production-grade plasma solvers like Gkeyll (a C/CUDA plasma simulation suite) into a gradient-based workflow is non-trivial. The ''Tesseract'' software addresses this challenge by providing a multi-physics differentiable abstraction layer made fully compatible with JAX (through the `tesseract_jax` adapter). This architecture ensures end-to-end differentiability while allowing seamless interchange between high-fidelity solvers (Gkeyll), neural surrogates, and analytical approximations for rapid, progressive prototyping.","short_abstract":"This work presents a case study of a heterogeneous multiphysics solver from the nuclear fusion domain. At the macroscopic scale, an auto-differentiable ODE solver in JAX computes the evolution of the pulsed power circuit and bulk plasma parameters for a compressing Z Pinch. The ODE solver requires a closure for the imp...","url_abs":"https://arxiv.org/abs/2511.13262","url_pdf":"https://arxiv.org/pdf/2511.13262v1","authors":"[\"Jack B. Coughlin\",\"Archis Joglekar\",\"Jonathan Brodrick\",\"Alexander Lavin\"]","published":"2025-11-17T11:23:16Z","proceeding":"physics.comp-ph","tasks":"[\"physics.comp-ph\",\"cs.CE\",\"cs.LG\",\"cs.MS\",\"physics.plasm-ph\"]","methods":"[]","has_code":false}