Design of the poloidal field system for KTX

The design of the poloidal field (PF) system includes the ohmic heating field system and the equilibrium (EQ) field system, and is the basis for the design of a magnetic confinement fusion device. A coupling between the poloidal and plasma currents, especially the eddy current in the stabilizing shell, yields design difficulties. The effects of the eddy current in the stabilizing shell on the poloidal magnetic field also cannot be ignored. A new PF system design is thus proposed. By using a low-μ material (μ=0.001, ε=1) instead of a conductive shell, an electromagnetic model is established that can provide a continuous eddy current distribution on the conductive shell. In this model, a 3D time-domain problem with shells translates into a 2D magnetostatic problem, and the accuracy of the calculation is improved. Based on these current distributions, we design the PF system and analyze how the EQ coils and conductive shell affect the plasma EQ when the plasma ramps up. To meet the mainframe design requirements and achieve an efficient power-supply design, the position and connection of the poloidal coils are optimized further.     

结构动力学特性分析中连接刚度的有限元建模对比研究

大型复杂结构都是由多个子结构组合而成的，其连接刚度会显著影响整体结构的动力学特性。本文已简单搭接板为例，采用有限元方法建立了连接刚度的体单元、加厚板单元、多点约束单元等有限元分析模型，获得了不同建模方式下，搭接板在外载荷作用下的静力学响应和无阻尼自由振动的动力学特性参数，对比分析了不同建模方式对结构动力学特性的影响。     

结构动力学特性分析中连接刚度的有限元建模对比研究

大型复杂结构都是由多个子结构组合而成的,其连接刚度会显著影响整体结构的动力学特性.本文已简单搭接板为例,采用有限元方法建立了连接刚度的体单元、加厚板单元、多点约束单元等有限元分析模型,获得了不同建模方式下,搭接板在外载荷作用下的静力学响应和无阻尼自由振动的动力学特性参数,对比分析了不同建模方式对结构动力学特性的影响.     

Comparison of methods for turbulence Doppler frequency shift calculation in Doppler reflectometer

The Doppler reflectometer(DR), a powerful diagnostic for the plasma perpendicular velocity(u⊥) and turbulence measurement, has been widely used in various fusion devices. Many efforts have been put into extracting the Doppler shift from the DR signal. There are several commonly used methods for Doppler shift extraction, such as the phase derivative, the center of gravity, and symmetric fitting(SFIT). However, the strong zero-order reflection component around 0 k Hz may interfere with the calcula...     

Bench test of interferometer measurement for the Keda Reconnection eXperiment device (KRX)

Motivated by the need of the electron density measurement for the Keda Reconnection eXperiment (KRX) facility which is under development, an interferometer system has been designed and tested in bench. The 320 GHz solid-state microwave source with 1 mm wavelength is used to fulfill the high phase difference measurement in such low temperature plasma device. The results of the bench test show that the phase difference is accurately measured. In contrast to tens of degrees of phase shift expected to be measured on the KRX, the system noise (∼1°) is low enough for the KRX diagnostics. In order to optimize the system for better performance, we utilize the Terasense sub-THz imaging system to adjust alignment. The interferometer system has also been calibrated via changing of the optical path length controlled by the piezo inertial motor. Simultaneously, high density polyethylene thin film is introduced successfully to change a tiny phase difference and test the sensitivity of the interferometer system.