Enhanced visualization of quench dynamics of HTS coils through embedded and distributed fiber optical sensing

• A novel method using Embedded and Distributed Fiber Optical Sensing (ED-FOS) technique is proposed for superconducting applications. • Precise, real-time monitoring of thermal responses and visualization of quench in high-temperature superconductor (HTS) coils are achieved. • ED-FOS demonstrates better both spatiotemporal resolution and temperature sensitivity than traditional methods. • The quench detection method is essential for ensuring the safety, reliability, and performance design of superconducting coils. The development of high-temperature superconducting (HTS) coils and magnets marks a significant advancement across various fields. To ensure their safety and reliability, thorough performance testing under extreme multi-field conditions is essential. This study introduces an innovative method that utilizes embedded and distributed fiber optical sensing (ED-FOS) in HTS pancake coils for precise real-time thermal monitoring and quench visualization. Incorporated during the manufacturing process, the ED-FOS sensors offer comprehensive and distributed measurements of thermal behavior during quenches. Our experiments demonstrate the ED-FOS effectively detects quenches caused by overcurrent and thermal issues. Unlike conventional techniques that rely on global voltage or magnetic field assessments, ED-FOS provides high spatiotemporal resolution and enhances temperature sensitivity. This capability allows for accurate, real-time identification and tracking of quench locations, which is essential for evaluating reliability and safety, as well as for improving performance. This advancement in HTS coil technology paves the way for wider application in critical fields and significantly enhances the design and management of superconducting coils.