摘要：As a flexible auxiliary heating method,the electron cyclotron resonance heating（ECRH） has been widely used in many tokamaks and also will be applied for the J-TEXT *** meet requirements of protection and fault analysis for the ECRH system on J-TEXT,signals of gyrotrons such as the cathode voltage and current,the anode voltage and current,etc should be transmitted to the control and data acquisition *** the high voltage environment of gyrotrons,isolation transmission module based on FPGA and optical fiber communication has been designed and *** test results indicate that the designed module has strong anti-noise ability,low error rate and high transmission *** delay of the module is no more than 5 μs which can fulfill the requirements.

摘要：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.

摘要：A real time system used to detect phase difference between two sinusoidal signals is proposed in this paper. The system is designed to process the phase signal of the far-infrared （FIR） hydrogen cyanide （HCN） interferometer on J-TEXT. It is based on zero-crossing detection and makes use of the digital circuit. Compared with a traditional zero-crossing phase detector, it doesn＇t need to sacrifice the time resolution to expand the phase range. The phase difference is divided into two parts, the integer part and the fraction part. In each detecting cycle, they are detected separately. It outputs digital signals that are more stable for transmission. A prototype was built on J-TEXT using discrete components. A practical method is proposed to deal with the counting error caused by the deviation of electronic components in manufacture. Reasonable results were obtained on the prototype. The phase resolution reaches 2π/64 in test, and can still be improved by raising the clock frequency.

摘要：The Q-band （33-50 GHz） fast sweep frequency modulated continuous wave （FMCW） reflectometry has been recently developed for electron density profile measurement on the Joint TEXT tokamak. It operates in ordinary mode （O-mode） with a 20 μs sweeping period, covering the density range from 1 × 10^19m 3 to 3 × 10^19m-3. On the bench test, a Yttrium Iron Garnet （YIG） filter is used for the dynamic calibration of the voltage controlled oscillator （VCO） to obtain a linear frequency sweep. Besides, the use of a power combiner helps to improve the sideband suppression level of the single side-band modulator （SSBM）. The reconstructed density profiles are presented, which demonstrate the capability of the reflectometry.

摘要：To meet the requirements of high performance THz-FEL （Free Electron Laser）, a compact scheme of FEL injector was proposed. A thermionic cathode was chosen to emit electrons instead of a photo-cathode with its complex structure and high cost. The effective bunch charge was improved to ~200 pC by adopting an enhanced EC-ITC （External Cathode Independently Tunable Cells） RF gun to extract micro-bunches; back bombardment effects were almost eliminated as well. Constant gradient accelerator structures were designed to improve energy to ~14 MeV, while the focusing system was applied for emittance suppressing and bunch state maintenance. The physical design and beam dynamics of the key components for the FEL injector were analyzed. Furthermore, start- to-end simulations with multi-pulses were performed using homemade MATLAB and Parmela. The results show that continual high brightness electron bunches with a low energy spread and emittance could be obtained stably.

摘要：The DC reactor is an important piece of equipment for restraining loop and ripple currents in the international thermonuclear experimental reactor （ITER） converter power supply system. As the reactor is operated at a steady state of 27.5 kA and needs to withstand a peak current of 175 kA, so the design of the DC reactor used in the ITER converter power supply system is necessary. A new water-cooling dry-type air-core reactor is designed in this work. The detailed structural parameters are calculated by theoretical formulas, and then the structure is optimized by electromagnetic simulation with ANSYS. Finally, thermal and dynamic stability analyses are performed to verify the temperature and stress at a rated current of 27.5 kA and pulsed current of 175 kA. The analysis results show that the temperature and stress meet the requirements of the ITER converter power supply system.

摘要：An EC-ITC （External-Cathode Independently Tunable Cells） RF gun was employed with the aim of obtaining short-pulse bunches with high peak current for a terahertz radiation source. A gridded DC gun plays a key role as the external injecting electron source of the ITC RF gun, the performance of which determines the beam quality in the injector and transport line. In order to make the beam well compressed in the ITC RF gun, the energy of the electrons acquired from the gridded DC gun should be 15 keV at most. A proper structure of the gridded gun with double-anode is shown to overcome the strong space- charge force on the cathode, which is able to generate 6 μs beam with 4.5 A current successfully.

摘要：In a poloidal field （PF） converter module, fuse protection is of great importance to ensure the safety of the thyristors. The fuse is pre-selected in a traditional way and then verified by finite element analysis. A 3D physical model is built by ANSYS software to solve the thermal- electric coupled problem of transient process in case of external fault. The result shows that this method is feasible.

摘要：The DC busbar is an important component for the ITER PF converter module to connect the converter and the reactor. This paper analyzes different cross-sections and different thermodynamic properties under natural-cooling and water-cooling conditions, and simulation is carried out by the software of the finite element method （FEM）. The result of the analysis shows that the water-cooling method is the better choice for the DC busbar.

摘要：A compact high-voltage repetitive nanosecond pulse generator(HRNPG)was developed for studying the technology of repetitive nanosecond pulse technology and its related *** HRNPG mainly consists of a repetitive charging module,a Tesla transformer and a sharpening *** its voltage lower than 1 kV,the primary repetitive charging circuit comprises two fast thyristors as its low-voltage *** spiral Tesla transformer acts as the main step-up component,and its peak transformation ratio is designed to be more than 100.A self-breakdown spark switch,*** sharpening switch,is used to sharpen the output of the transformer and to generate nanosecond *** HRNPG prototype is capable of generating pulses of 100 kV in peak with rise time 30 ns and the maximum repetition rate of 500 Hz on a 6 k *** results show,without any magnetic core,the developed Tesla transformer prototype can easily output high voltage while keeping itself small in size and light in weight,which is of significance for the compactness and portability of the pulse *** N2-insulated spark switch operated well at voltage close to 100 kV and the repetition rate within several hundreds of hertz.