Technological Advances
The intense heat generated in gyrotrons, comparable to that in nuclear reactors, necessitates advanced cooling systems. Thales has developed and patented mini channel cooling systems that significantly enhance heat extraction while minimizing thermo-mechanical stress. This allows for higher electromagnetic field intensities in the cavity, improving interaction efficiency and output power without increasing the order of the operating mode.
The design of Magnetron Injection Guns (MIGs) is critical to ensuring a high-quality electron beam. Thales has introduced a new cathode structure that mitigates the effects of thermal expansion, ensuring precise positioning of the emitter and maintaining beam quality.
Parasitic waves can degrade performance by causing instabilities in the electron beam. Innovations in beam tunnel design, such as those developed by KIT, include stacked ceramics and metallic rings that reduce unwanted interactions, maintaining the beam’s focus and stability.
Gyrotrons in Use and Development for Fusion Experiments
Thales has been at the forefront of gyrotron development for fusion, with several models currently in use or under development, including:
- TH1509U: Provides 1 MW for 3600 seconds at 170 GHz, developed for ITER and DTT.
- TH1510: Dual-frequency gyrotrons (84-126 GHz) providing over 1 MW, currently operational at TCV, EPFL-SPC in Switzerland, with another unit being deployed in 2024.
- TH1511: 1 MW CW gyrotron at 105 GHz, being tested for WEST at CEA, in France.
- TH1512: 1 MW long-pulse gyrotron at 117.5 GHz, under manufacturing for DIII-D at General Atomics in the United States in 2024.
- TH1507: Nine units providing 1 MW for 1800 seconds at 140 GHz, supporting the W7-X Stellarator in Greifswald, Germany, with a new 1.5 MW prototype under test in 2024.
These gyrotrons represent the cutting edge of what is currently possible, pushing the boundaries of power and efficiency in fusion energy applications.
Conversion Efficiency
Maximizing the Radio Frequency (RF) energy produced from input electric energy is crucial for improving the overall efficiency of gyrotrons. The depression scheme, which involves integrating multiple electrodes at different voltages, is one such innovation that allows for reducing cathode voltage while maintaining RF power output, thus increasing total efficiency.
The development of gyrotron technology is crucial for the success of future fusion reactors. This article examines the future directions for gyrotron development, including higher power and frequency capabilities, advanced materials, and the role of industry collaboration.
Future Directions
- Higher Power and Frequency: Future gyrotrons must operate at higher power levels and frequencies to meet the demands of next-generation fusion reactors. Ongoing research focuses on developing gyrotrons that can operate above 200 GHz, essential for advanced heating and current drive systems.
- Advanced Materials and Cooling Techniques: New materials and cooling techniques are being explored to improve thermal management, allowing gyrotrons to operate continuously at higher power levels without overheating.
- Simulation and Modelling: Advanced simulation and modelling tools are being used to predict and optimize gyrotron behaviour under various operating conditions, ensuring reliability and performance.
EUROfusion and Industry Collaboration
The collaboration between EUROfusion, Thales, and other industry partners is essential for advancing gyrotron technology. These partnerships are vital for bringing new innovations from the lab to practical application in fusion reactors.
Spotlight on Alberto Leggieri
Alberto Leggieri is an RF Specialist Engineer at Thales and has been instrumental in advancing gyrotron technology. His work includes the development of high-power gyrotrons and innovative cooling solutions, which are critical to the success of fusion energy projects. His contributions highlight the importance of individual expertise in driving technological advancements in the field.
“I hope to see gyrotron technology continue to evolve, becoming more efficient and powerful, to support the next generation of fusion reactors. Ultimately, I believe that fusion energy will play a crucial role in addressing global energy demands and environmental challenges. The future of gyrotron technology is closely tied to the success of fusion energy. Through continued innovation and collaboration, we are moving closer to realizing the potential of fusion as a sustainable energy source.”
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