GATM: A 3-D FE Fusion Magnet Model and Application to DIII-D and Next-generation Devices

The General Atomics Tokamak Model (GATM) is a recently developed finite element (FE) environment for assessing the performance of tokamak magnet-plasma systems. Its generic environment is designed to assess magnet performance parameters for existing tokamaks, such as Doublet-III-D (DIII-D) and next-generation tokamak. GATM’s environment consists of a number of models, including a Comsol 3-D FE model and routines connecting this model to other GA tools. GATM consists of a 2-D axisymmetric module characterizing Poloidal Fields (PFs) system magnetic properties, including an equilibrium fitting code (EFIT) plasma representation. The 2-D module contains a central solenoid (CS) structural model for stress and deflection assessment. Toroidal field (TF) coils are characterized by a 3-D magnetics module for TF calculations and simulation of TF nonaxisymmetric ripple. PF and TF magnetics models provide input to a 3-D TF structural module, which simulates both in-plane and out-of-plane stress. A 3-D TF center post module uses input from the other three modules to evaluate the performance of a superconducting coil including details of the case, winding-pack, and superconducting cable. Model geometry, (Plasma, TF, CS, PF, and structures) is fully parametrized and allows for rapid assessment of arbitrary tokamak configurations. The GATM model is under development and is intended to interface with other general atomics models including: GA System Code (GASC), dynamic tokamak system model (TokSys), recently developed FUsion Synthesis Engine (FUSE), and DIII-D database, including EFIT. Models and current states generated in the GATM environment are output to engineering relevant codes ANSYS and SolidWorks. The article provides an overview of the present GATM environment and its application to DIII-D’s TF coil and an advanced tokamak (AT) Fusion Pilot Plant (FPP).