HT-7超导托卡马克总控系统的设计与实现

为了适应当前HT-7及今后EAST装置运行的需要,对原有总控系统进行改造,扩展了系统的功能。新的总控系统主要包括放电监控子系统、分布式定时及触发子系统、控制参数设置子系统、事件触发子系统、手动微调子系统。文章详细介绍了各个子系统的硬件组成结构、软件设计和实现过程。     

Electron temperature fluctuation in the HT-7 Tokamak plasma observed by electron cyclotron emission imaging

The fluctuation of the electron temperature has been measured by using the electron cyclotron emission imaging in the Hefei Tokamak-7 (HT-7) plasma. The electron temperature fluctuation with a broadband spectrum shows that it propagates in the electron diamagnetic drift direction, and the mean poloidal wave-number $\bar{k}_{\theta}$is calculated to be about 1.58 cm^-1, or \bar{k}_θ ρ_s≈ 0.34. It indicates that the fluctuation should come from the electron drift wave turbulence. The linear global scaling of the electron temperature fluctuation with the gradient of electron temperature is consistent with the mixing length scale qualitatively. Evolution of spectrum of the fluctuation during the sawtooth oscillation phases is investigated, and the fluctuation is found to increase with the gradient of electron temperature increasing during most phases of the sawtooth oscillation. The results indicate that the electron temperature gradient is probably the driver of the fluctuation enhancement. The steady heat flux driven by electron temperature fluctuation is estimated and compared with the results from power balance estimation.     

柱等离子体中磁流体力学波之间的耦合

采用柱螺旋坐标系 ,把广义磁流体力学方程组简化为四元一阶微分方程组。在ω/ωci→ 0时 ,该方程组化为Hain L櫣ｓｔ方程 ;而当p→ 0 时 ,即是KAppert理论。在这两种情况下 ,Alfv啨ｎ波共振层都是奇异的。Alfv啨ｎ波共振层的奇异性来源于极限的选取谠独爰薜那?,离子的惯性会使理想磁流体中Alfv啨ｎ波共振层的奇异性消失 ,且使磁流体力学波之间相互耦合     

KT5C 托卡马克分布式高速数据采集系统

介绍了小型磁约束环装置KT5C 上利用校园高速局域网络, 低成本实现的分布式高速数据采集系统。当在不同位置的三个用户同时发送采集请求时, 该系统能在10 秒左右完成每个用户5 个通道的采样频率为5MHz采样长度为512kB 的数据采集。实现了远程多用户同时操作, 提高了大量实验数据的采集效率。     

关于HL—1M马赫探针及其诊断数据处理

在简要回顾了马赫探针主要物理模型的基础上,论述了ＨＬ－１Ｍ装置的马赫探针诊断。分析表明,马赫探针阵列设计中的问题和对非平行流数据处理物理模型上的问题,导致处理所得物理实验数据失去意义,为了获得可靠结果,建议改进探针阵列设计,并采用正确数据处理方法。     

HL-2A装置气体击穿延迟时间

气体击穿延迟时间实验数据表明,HL-2A装置的气体击穿过程可以用修改了的有电极放电汤森德电离公式,并考虑电子的几何损失来进行描述。     

Model for the Error Field Effect on Resistive Wall Modes

A semianalytic multimode model that includes the instantaneous influence of a static error field on the resistive wall mode (RWM) is presented. The asymptotic behavior of the RWM as the marginal stability is approached, including the influence of the error field, is discussed. The influence of neighboring modes on the central harmonic modes is explored, allowing a less destabilizing error field spectrum to be proposed. The model has been applied to a plasma surrounded by a HBT‐EP tokamak type feedback system. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Effect of shear equilibrium flow in Tokamak plasma on resistive wall modes

A code named LARWM with non-ideal magnetohydrodynamic equations in cylindrical model is used to describe the instability in Tokamak plasma surrounded by a conducting wall with finite resistivity. We mainly take three factors related to the shear equilibrium plasma flow into consideration to study the stabilizing effect of the shear flow on the resistive wall modes (RWMs). The three factors are the velocity amplitude of flow, the shear rate of flow on plasma surface, and the inertial energy of equilibrium plasma flow. In addition, a local shear plasma flow is also calculated by the LARWM code. Consequently, it is found that the inertial energy of the shear equilibrium plasma flow has an important role in the stabilization of the RWMs.     

A Model for the Neoclassical Toroidal Viscosity Effect on Edge Plasma Toroidal Rotation

A semianalytic expression for the edge plasma angular toroidal rotation frequency that includes the neoclassical toroidal viscosity braking influence is obtained. Based on the model presented in a previous paper [I.G. Miron, Contrib. Plasma Phys. 53 , 214 (2013)], the less destabilizing error field spectrum is found in order to minimize the nonlinear effect of the NTV on the toroidal rotation of the edge of the plasma. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

如何从偏振仪测量信息中获得q分布

介绍了一种通过实验测量获得的法拉第旋转角和电子密度分布获得托卡马克等离子体安全因子分布的模拟计算方法.该方法采用大环径比的近似,适用于平衡态等离子体物理分析.在欧姆和电子回旋加热的放电情况下,获得了合理的安全因子q分布和电流密度分布,计算结果与软X射线测量的结果一致.