Abstract
A long pulse Electron Cyclotron Resonance Heating (ECRH) system is developed on EAST tokamak for plasma heating and current profile tailoring. The ECRH system is designed to operate at 140GHz and to inject 4MW CW power. With respect to the physical objectives of the newly built ECRH system, a quasi-optical launcher is designed to inject 4MW continuous wave into plasma through an equatorial port. Gaussian beams delivered from evacuated corrugation waveguides will be focused and reflected by high thermal conductive metal mirrors, and then steered by using push-rod steering mechanism with entire scanning range of ±25° toroidally and over 30° poloidally in plasma cross section. The mirrors are carefully designed with mega watts power handling capability and optimum optical characteristics. The performance of steering mechanism has been tested before installation, an open-loop control system for ECRH launcher has been implemented for required mirror movement and proper polarization between plasma discharges. This paper will present the overall design and progress of the launcher, along with the performance in EAST campaigns. Considerations and possible upgrade of the design features relevant to long pulse operation are discussed.
Highlights
Electron Cyclotron Resonance Heating (ECRH) scheme has many advantages in magnetic fusion devices, e.g. perfect power coupling with the plasma, highly localized power deposition [1,2,3,4] and good theoretical understanding of the wave-particle interaction physics
A long pulse ECRH program is launched on EAST under the support of National Magnetic Confinement Fusion Science Programs of China since 2011
It will be used for central heating and current drive applications as well as off-axis control of magnetohydrodynamic (MHD) instabilities such as Neoclassical Tearing Modes (NTMs), sawtooth, and Edge Localized Mode (ELM)
Summary
Electron Cyclotron Resonance Heating (ECRH) scheme has many advantages in magnetic fusion devices, e.g. perfect power coupling with the plasma, highly localized power deposition [1,2,3,4] and good theoretical understanding of the wave-particle interaction physics. As one of the most promising external auxiliary heating and current drive methods, ECRH provides large flexibility and complies with diverse physics demands. A long pulse ECRH program is launched on EAST under the support of National Magnetic Confinement Fusion Science Programs of China since 2011. It will be used for central heating and current drive applications as well as off-axis control of magnetohydrodynamic (MHD) instabilities such as Neoclassical Tearing Modes (NTMs), sawtooth, and Edge Localized Mode (ELM). The launcher should be compatible with the requirements of long pulse power handling and flexible control of localized power deposition These design goals present a number of challenges. This paper describes the overall design and progress of the launcher
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