Design of the Transmission Lines for 140 GHz ECRH System on HL-2A

A new 140 GHz/2 MW/3 s electron cyclotron resonance heating （ECRH） system composed of two units is now being constructed on HL-2A. As a part of the system, two trans- mission lines marked No.7 ＆ 8 play the role of carrying microwave power from two gyrotrons to the tokamak port. Based on the oversized circular corrugated waveguide technology, an evacu~ ated transmission system with high power capability and high transmission efficiency is designed. Details are presented for the design of the corrugated waveguide, the layout of the proposed lines and the vacuum pumping system. Then mode conversion losses due to coupling, misalignment, bends and gaps are discussed to serve as a reference for analyzing the transmission efficiency and alignment. Finally, a dual-modes propagation case consisting of the HEll and LPn even modes is discussed.     

ECRH Launcher for Four-Beam Injection on HL-2A Tokamak

An Electron Cyclotron Resonance Heating (ECRH) launcher for four-beam injection has been installed on the HL-2A tokamak and used in plasma heating experiments. By the launcher, four EC wave beams can be injected into the tokamak through a φ350 mm port, which are generated from 2 sets of 68 GHz/1 s and 2 sets of 68 GHz/1.5 s gyrotron tubes manufactured by GYCOM, with maximum output power of 500 kW for each. In this paper, the properties of the EC beam in the launcher and plasma are presented: at the centre of the cross section of the tokamak, the beam radius is 31.7 mm; thermal analysis of a 3D model indicates that the peak temperature increase would be only 30 o C at the mirror surface for a 500 kW/1 s pulse; ray-tracing calculation predicts satisfactory power deposition. In the plasma experiment, six beams including four beams from this launcher and two from another launcher have been injected simultaneously. Besides, obtaining ELM-y H-mode discharges, the ECRH system shows reliability and stability of the launcher functions.     

Development of a 140 GHz Steerable Launcher for the HL-2A ECRH System

A new electron cyclotron resonance launcher system has been designed and installed on heating and current drive （ECRH/ECCD） the HL-2A tokamak to inject four beams and enable continuous millimeter-wave beam scanning independently in the toroidal and poloidal direc- tions for ECRH/ECCD experiments. The launcher is connected to four mm-wave lines capable of transmitting high power up to 3 MW with two 1 MW/140 GHz/3 s and two 0.5 MW/68 GHz/1 s beams. Based on ray tracing simulation using the TORAY-GA code, tile scanning range of wave beams is -15~~15~ in the toroidal direction and 0~~10~ in the poloidal one for 140 GHz beams, which could cover half of the cross section of plasmas and can satisfy the requirements of advanced physical experiments. The beam radii in the plasma is 17.1 mm and 20 mm for the two 140 GHz beams and 29.5 nnn for the two 68 GHz beams, respectively, allowing a very high localization of the absorbed power. The performance of the steering system was proven to be reliable and the linearity is perfect between the displacement of drive shaft and rotate angle of mirror. Addition- ally the injection performance of the wave beams was optinfized by simultaneously setting the injection angle and the polarization to realize desirable pure O- or X-mode injection.     

高功率回旋振荡管在HL-2A装置上的应用研究

电子回旋共振加热(ECRH)因其加热的定域性好、高效性和易操作等特点,成为许多托卡马克、仿星器等磁约束装置普遍采用的加热手段之一.微波波源高功率回旋振荡管是ECRH系统的核心设备,本文详细介绍了 HL-2A装置ECRH系统的调试运行及实验,其中6套功率为0.5 MW、频率为68 GHz的ECRH系统可稳定运行输出2.5...