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The European 1 MW, 170 GHz industrial CW prototype gyrotron has been designed within EGYC (European GYrotron Consortium) in collaboration with the industrial partner Thales Electron Devices (TED) and under the coordination of Fusion for Energy (F4E). This is a conventional (hollow) cavity gyrotron that is based on the 1 MW, 170 GHz short-pulse (SP) modular gyrotron, which has been designed and manufactured by KIT in collaboration with TED. The SP prototype has been tested in multiple experimental campaigns since 2015 and the nominal cavity mode TE32,9 is exited at 170.1 GHz, producing RF power above 1 MW with 35 % interaction efficiency. The first phase of the experiments with the CW industrial gyrotron was successfully completed at KIT in 2016, verifying most of the ITER specifications. Short pulses (

This presentation reports on the 2019 status and focus areas in the development of an advanced gyrotron for the European DEMOnstration Fusion Power Plant (EU DEMO). As specified within the EUROfusion Work Package Heating and Current Drive (WP HCD), the requirements for the gyrotron are as follows: (i) ≥ 2 MW of RF output power at frequencies ≥ 200 GHz; (ii) a total efficiency ≥ 60 %; (iii) the options for multiple-purpose/multi-frequency operation and fast frequency step-tunability within a limited bandwidth of approximately ± 10 GHz. To meet those targets, the R&D activities are organized in five main branches: (1) the experimental verification of the advanced coaxial-cavity gyrotron technology at long pulses; (2) the development of an advanced coaxial-cavity gyrotron that meets the EU DEMO requirements; (3) the fundamental research on multi-stage depressed collectors for enhanced energy recovery; (4) the development of large broadband diamond windows to allow for fast frequency tunability of the gyrotron: (5) the studies on further innovations and improvements of critical gyrotron components and tools in view of optimization of performance, reliability, and industrialization. Possible exchange: Within EUROfusion the EU is working on specific gyrotrons for future EU DEMO. There is a collaboration possible. Additionally, the different institutions within EU are open for any discussion on possible collaboration with regards to tools developments, development of future high-power high-frequency gyrotron teststands, measurements technologies and prospective R&D of further advances in gyrotron technology. If the collaboration is performed within EUROfusion, then the topics will be in line with the approved WPHCD work program.

During the ongoing pre-concept phase (2014 – 2020) for a possible future European DEMOnstration Fusion Power Plant (DEMO) the activities within EUROfusion WP HCD EC Gyrotron R&D and Advanced Developments are focusing on options for near-term solutions, and, at the same time, on long-term even more advanced options. The near-term target for DEMO is to realize pulsed operation. According to the current baseline it will probably use an EC system operating at 170 GHz and 204 GHz is being assessed, whereas the long-term target aims for steady-state operation and frequencies for current drive up to 240 GHz. Common targets for both are an RF output power per unit of significantly above 1 MW (target: 2 MW) and a total gyrotron efficiency of significantly higher than 60 %. Frequency step-tunability and multi-purpose/multi-frequency operation have to be considered. Those targets shall be achieved by considering the coaxial-cavity gyrotron technology and advanced technologies for key components (e.g. CVD diamond-disk Brewster angle window). Advanced simulation and test tools are complementing the research and developments. Gyrotron development is additionally supported by a significant investment into a new multi-megawatt long-pulse gyrotron test stand which is under final installation at KIT currently.

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Magnetic fusion is one approach to generate thermonuclear fusion power in an environmental friendly way. The Electron Cyclotron Resonance Heating is considered as the major concept for startup, heating and control of the fusion plasma. Megawatt-class gyrotrons generate the required microwave power. This work focuses on advanced key components and technologies for a DEMO relevant 2 MW gyrotron. One major focus is on the development of advanced Magnetron Injection Guns. Another focus is on the red