Diagnostic System for a 20 Tesla, Toroidal, Single Turn Magnet Prototype for Fusion Ignition

The Center for Electromechanics has designed, fabricated, and is now operating a prototype of a full torus, 20 Tesla (T) on-axis, single turn, toroidal field (TF) magnet system powered by the Balcones Homopolar Generators (HPGs). This magnet system is part of the Ignition Technology Demonstration (ITD) program for the fusion ignition experiment (IGNITEX). The six HPGs connected to the prototype magnet in parallel are capable of producing a 9 MA, 150 ms, current pulse required for a 20 T ITD test. The diagnostic system for the prototype magnet is designed to determine strains, temperatures, and magnetic fields at several locations in the TF magnet. These values are used to verify numerical predictions by electromechanical and thermomechanical analyses. Operating conditions for the instrumentation inside the cryogenically cooled magnet are extreme; localized temperatures inside the magnet can rise from - 196°C to 200°C during the current pulse and the magnet field levels near the inner leg surface can rise to 30 T in 30 ms. The specifications, testing, and layout of the diagnostic and data acquisition systems for the ITD prototype are presented in this paper.