Superconductivity for Nuclear Fusion: Past, Present, and Future

Within fusion research and development, there are three main categories of fusion devices: magnetic confinement fusion, inertial confinement fusion, and magneto-inertial confinement. The focus on achieving power production has historically centered around magnetic confinement fusion, employing devices such as tokamaks, stellarators, and spheromaks. The plasma confinement in these machines relies on powerful magnetic fields generated from large, complex electromagnetic systems containing superconducting coils. Superconductivity, or the flow of current without resistance at low temperatures, allows the electromagnets to fulfill the demanding requirements of fusion devices. Analyzing the history of superconducting magnets in the application of fusion energy production provides necessary insight into the current state of the technology and allows for identification of current and future trends in research and development. Throughout its history, fusion research has experienced cyclic periods of depression followed by renewed interest. Breakthroughs in superconducting technologies have played a part in stimulating these periods of renaissance, cementing its role as an enabling technology for fusion. Future trends in research aim to address several challenges in using superconducting magnets in fusion devices, including manufacturing difficulties, irradiation and long-term availability, quench detection and protection, and finally the high cost of the materials and cryogenic cooling. The resolution of these issues is crucial for advancing fusion devices toward practical energy production.