Fusion Science and Technology / Volume 53 / Number 1 / January 2008 / Pages 246-253
Technical Paper / Special Issue on Electron Cyclotron Wave Physics, Technology, and Applications - Part 2
The ITER electron cyclotron heating (ECH) baseline scheme (2001) is composed of 24 gyrotrons, each generating 1 MW of radio-frequency power at 170 GHz in addition to 3 gyrotrons (1 MW) at 120 GHz for breakdown assist. Considering an efficiency of 45%, which can be achieved with the depressed-collector-type gyrotron (CPD), the amount of electrical power would be in the range of 55 MW. This paper has two purposes. First, it presents requirements that will be imposed on the electrical power supplies with regard to the updated physics needs for ITER presently being discussed. Demanding parameters (like modulation capability, transient margin, and fault clearing) will be described. In this context, the consequences of those new requirements on the technical choices and the impact on the complexity of the power supplies will be discussed. Second, two possible schemes for the ITER reference power supply design for the ECH system will be compared. The advantages (and respective disadvantages) of each solution will be highlighted taking care of the requirements previously presented. In conclusion, a proposal is presented for a revised ECH power supply structure.