Transformation of the trapped flux in a SC disc under electromagnetic exposure

TL;DR

This study examines how trapped magnetic flux in superconducting disks responds dynamically to stepwise external magnetic field changes, revealing significant flux variations and potential impacts on device reliability.

Contribution

It provides new insights into the flux transformation process under magnetic shocks and introduces a scaling analysis of flux profiles in superconducting disks.

Findings

40-50% change in trapped flux per 600 G magnetic step at 5 K

Flux response correlates directly with external magnetic field changes

Scaling analysis yields roughness exponents between 0.435 and 0.475

Abstract

Superconducting permanent magnets (SCs) with trapped magnetic flux are used in technical devices (motors, generators, etc.). These magnets endure repeated magnetic "shocks" during operation, which can affect their performance. In this work, we investigated the dynamic behavior of magnetic induction in the trapped flux in an SC disk when exposed to stepwise changes in the external magnetic field, simulating these operational shocks. Our results reveal a direct correlation between the stepwise changes in the magnetic field and the trapped flux response, with each increase or decrease in the field inducing a corresponding 40-50% change in trapped flux for a 600 G field step at temperature of 5 K. The magnitude of these changes depends on the external parameters and their dynamics could lead to additional energy dissipation and potential heating, which may affect the reliability of SC magnets in applications. A scaling analysis of the induction flux profiles, revealing roughness exponents in the range of 0.435 to 0.475 was performed as well, and we determined the Hausdorff dimension of the surface structure.