Speaker
Description
Within Europe and worldwide KIT is strongly involved in the development of high power gyrotrons for application in ECRH and ECCD in magnetic confinement of fusion plasmas. KIT is one of the leading labs in Europe for gyrotron development including design of gyrotron components as well as experimental verification of the integral systems in short pulse and long pulse/CW operation. KIT is providing major contributions for gyrotron projects on W7-X, ITER, DTT, CEA-WEST and GA-DIII-D. Exactly for that reasons, the new gyrotron FULGOR test stand (FUsion Long Pulse Gyrotron LabORatory) has been built and is currently in the final commissioning stage. The FULGOR test stand was developed for gyrotron testing offering up to 10 MW of electrical power at 90 kV and 120 A available in CW operation regime. With a body power supply (BPS), being the fixed part of the test stand, a gyrotron operation of conventional single-stage depressed collector is possible. In addition, the design of the main power supply supports the operation of so-called multi-staged depressed collectors, which are supposed to enhance the overall efficiency of gyrotrons beyond 60 %. The integral part of the FULGOR gyrotron test stand is the cryogen-free superconducting magnet. Due to its challenging technical specification to satisfy the requirements for testing of the fusion gyrotrons in the future (i.e.10.5 T combined with a large size of the bore-hole of 240 mm and a dipole coils system for fine magnetic field alignment inside the cavity), the procurement process of the magnet is delayed. But, the manufacturing is proceeding properly and the delivery is expected for end of 2024. However, in the meantime, the final validation and commissioning of the FULGOR test stand takes place with a 105 GHz 1 MW CEA-WEST gyrotron, installed in a dedicated 4.2 T cryogen-free magnet, temporary installed in the test stand. During the first short-pulse operation phase, a stable gyrotron operation at the specified 1 MW RF power was demonstrated. During those tests, the maximum RF power up to 1.2 MW has been achieved, with efficiencies close to 35 % and 45 %, for both non-depressed and depressed collector operation, respectively. The continuation of the experiments in long-pulse operation regime is planned in March 2024. Currently, the final preparations of the FULGOR test stand for first long-pulse operation are in progress. Recent results achieved during the operation with the CEA-WEST gyrotron will be presented and discussed.
Acknowledgments:
This work has been carried out within the framework of the EUROfusion Consortium, funded by the European Union via the Euratom Research and Training Programme (Grant Agreement No 101052200 — EUROfusion). Views and opinions expressed are however those of the author(s) only and do not necessarily reflect those of the European Union or the European Commission. Neither the European Union nor the European Commission can be held responsible for them.
