From Series Production of Gyrotrons for W7-X Toward EU-1 MW Gyrotrons for ITER

Abstract

Abstract-Europe is devoting significant joint efforts to develop and to manufacture MW-level gyrotrons for electron cyclotron heating and current drive of future plasma experiments. The two most important ones are the stellarator Wendelstein W7-X at Greifswald and the tokamak ITER at Cadarache. While the series production of the 140 GHz, 1 MW, CW gyrotrons for the 10 MW ECRH system of stellarator W7-X is proceeding, the European GYrotron Consortium (EGYC) is presently developing the EU-1 MW, 170 GHz, CW gyrotron for ITER. The initial design had already been initiated in 2007, as a risk mitigation measure during the development of the advanced ITER EU-2 MW coaxial-cavity gyrotron. The target of the ITER EU-1 MW conventional-cavity design is to benefit as much as possible from the experiences made during the development and series production of the W7-X gyrotron and of the experiences gained from the earlier EU-2 MW coaxial-cavity gyrotron design. Hence, the similarity of the construction will be made visible in the present article. During 2012, the scientific design of the ITER EU-1 MW gyrotron components has been finalized. In collaboration with the industrial partner Thales Electron Devices (TED), Vélizy, France, the industrial design of the technological parts of the gyrotron is being completed. A short-pulse prototype is under development to support the design of the CW prototype tube. The technological path towards the EU ITER-1MW gyrotron and the final design will be presented. . Both experiments are relying on electron cyclotron resonance heating (ECRH) as the main heating method for steady state operation, while in addition it is planned for ITER to apply electron cyclotron resonance technique for current drive (ECCD). ECRH & ECCD offer the compatibility to the various physics demands, such as controlled plasma start-up, steady state plasma control, and performance optimization by plasma profile shaping. It offers excellent coupling to the plasma, remote launching and very good localization of the absorbed power. Index Terms-PlasmaThe construction of the stellarator W7-X is almost completed and the device is approaching the commissioning phase [3]. W7-X operation will be supported by a 10 MW continuous wave ECRH system working at 140 GHz in 2 nd harmonic X-or O-mode. To date, the ECRH-system of W7-X is in stand-by with already 5 out of 10 gyrotrons operational. The series production of the W7-X 1 MW, CW gyrotrons [4,5] for the 10 MW ECRH system is proceeding.The European gyrotron development for ITER started with an advanced 170 GHz, 2 MW coaxial-cavity design. RF tests with an industrial CW prototype were done at the European test facility at EPFL-CRPP Lausanne in December 2011 [6]. The prototype did show an excellent voltage stand-off. It was directly possible to excite the nominal operating TE 34,19 -mode. The output RF-beam intensity was in good agreement with the expected one. Without further optimization, the RF output power reached the level of almost 2.1 MW in short-pulse (1 ms) operation with sin...

Recent progress in the upgrade of the TCV EC-system with two 1MW/2s dual-frequency (84/126GHz) gyrotrons

“…The gyrotron design is essentially based on modifications of the W7-X gyrotron [6][7][8] in which some sub-components have been redesigned (see Fig. 3 [9]) using the most advanced models.…”

Status of Europe’s contribution to the ITER EC system

“…The EU gyrotrons will be installed for the 2 nd plasma operation phase, occurring about 3 years after the 1 st plasma. The current EU gyrotron activities for ITER focus on the development of a 170 GHz, 1 MW, 3600 s TE 32,9 -mode cylindrical-cavity gyrotron, the manufacturing design of which is chosen as close as possible to the design of the 140 GHz, 1 MW, 1800 s gyrotron for the W7-X Stellarator at IPP Greifswald [3,4]. The series production of the W7-X gyrotron at Thales Electron Devices (TED), France, is presently in the final phase (5 gyrotrons being accepted by IPP, 1 additional gyrotron is in final acceptance phase at IPP), and, therefore represents an excellent basis for the industrialisation of the gyrotrons for ITER [5].…”

Development of Mode Conversion Waveguides at KIT

“…A mirror-line launcher has also been designed for the TE 32,9 -mode, 170GHz, 1MW EU ITER gyrotron which is currently under development in Europe [12,13]. The ideal Gaussian distribution used as the target function on the launcher aperture in the optimization of the launcher is shown in Figure 3.…”