Non-linear diffusion and inhomogeneity of the magnetic field in single-turn coils: Insights from 3D multiphysics modeling

TL;DR

This paper uses 3D multiphysics finite element modeling to analyze the nonlinear diffusion of electric current, temperature, and magnetic fields in single-turn coils during high-field pulsed magnet operation.

Contribution

It provides detailed insights into the inhomogeneous electromagnetic and thermal phenomena in single-turn coils through advanced 3D multiphysics simulations.

Findings

Revealed highly nonlinear diffusion of electric current, temperature, and magnetic fields.

Identified sources of inhomogeneous magnetic fields in the coil.

Demonstrated the importance of 3D modeling for understanding coil behavior.

Abstract

The single-turn coil method is a destructive pulsed magnet for generating over 100 T with a few $\mu$-second pulse duration, and it inevitably causes the coil to explode. The temporal and spatial distributions of the electric current and magnetic field are highly inhomogeneous, arising from the skin effect, rapid temperature rise, and coil deformation. To grasp the dynamic phenomena in the single-turn coil, we conducted a finite element analysis using multiphysics simulation. We employed finite element method calculations using a fully 3D model of the single-turn coil with broken cylindrical symmetry. The calculated result revealed highly nonlinear diffusion of electric current, temperature, and magnetic fields, which are the sources of the inhomogeneous magnetic fields inside the single-turn coil in time and space.