Magnetohydrodynamic effect of internal transport barrier on EAST tokamak

An internal transport barrier (ITB) can be formed on EAST in exploring high-parameter operation. Previous studies show that safety factor (q) profiles, Shafranov shift and magnetohydrodynamic behaviors could be helpful in ITB formation by suppressing anomalous transport. Recently, electron density evolution with high resolution demonstrates that fishbone could be dominant in electron density ITB formation and sustainment. The power threshold is low in the fishbone condition and the electron density profile is determined by traits of fishbone. Simulation shows that the low-k ion mode is suppressed by fishbone. Direct measurement of turbulence in the inner region shows that the internal kink mode could sustain an electron temperature ITB by suppressing the trapped electron mode. The multi-scale interaction between the kink mode and turbulence by current could be key in sustaining high-electron-temperature long-pulse operation.     

双子表活剂解除低渗透油藏水锁伤害实验研究

双子表活剂比常规表活剂具有更低的表界面张力,是目前在油田助剂领域应用比较广泛的一种新型表活剂。低渗透油井作业过程中,经常发生作业液渗滤到近井地带,使油气井产液量和油气产量下降,给油气田正常生产带来困扰。胜利油田昌邑分公司CH68区块为一低渗透区块,多口油井作业后受到水锁伤害而造成产量下降。在分析水锁伤害机理后对目的区块进行双子表活剂解除水锁伤害技术评价及现场应用,现场施工效果显著。     

Kinetic equilibrium reconstruction for the NBI-and ICRH-heated H-mode plasma on EAST tokamak

The equilibrium reconstruction is important to study the tokamak plasma physical processes.To analyze the contribution of fast ions to the equilibrium,the kinetic equilibria at two time-slices in a typical H-mode discharge with different auxiliary heatings are reconstructed by using magnetic diagnostics,kinetic diagnostics and TRANSP code.It is found that the fast-ion pressure might be up to one-third of the plasma pressure and the contribution is mainly in the core plasma due to the neutral beam injection power is primarily deposited in the core region.The fast-ion current contributes mainly in the core region while contributes little to the pedestal current.A steep pressure gradient in the pedestal is observed which gives rise to a strong edge current.It is proved that the fast ion effects cannot be ignored and should be considered in the future study of EAST.     

Spontaneous current relaxation in NBI heated plasmas on EAST

We report on current profile evolution in EAST NBI driven plasmas where two neutral beams are injected,one during the current ramp phase and the second during flattop.At the end of the current ramp phase,it is found that a flat q profile with q0?~?1 is achieved with low magnetic shear in the core.It is observed that plasma current and density both relax much faster than resistive time,even in the absence of sawtooth activity when H–L transition occurs.Density fluctuations associated with magnetic perturbations(3/2) as a precursor to the H–L transition are observed.It is likely that these modes play a role in fast current transport.     

HCN Laser Interferometer on the EAST Superconducting Tokamak

A single-channel far-infrared （FIR） laser interferometer was developed to measure the line averaged electron density on the EAST tokamak. The structure of the single-channel FIR laser interferometer is described in detail. The evolution of density sawtooth oscillation was measured by means the FIR laser interferometer, and was identified by electron cyclotron emission （ECE） signals and soft X-ray intensity. The discharges with and without sawtooth were compared with each other in the Hugill diagram.     

论水利工程中的施工管理

水利工程是我国国民经济和社会发展的重要物质基础。长期以来,水利工程在防洪、排涝、防灾、减灾等方面对国民经济的发展做出了重大的贡献,同时在工业生产、农业灌溉、居民生活、生态环境等生产经营管理中发挥了巨大的作用。而水利工程施工是水利工程建设的重要阶段,是将蓝图变成现实的过程。因此必须采取切实有效的措施,提高施工管理水平,提高工程建设的质量。     

面向天基实时系统的QoS监控算法研究

天基网研究正日益得到广泛的重视,但如果天基网缺乏相应的QoS机制,系统过载时将会造成巨大的损失。一个提供多类服务的基于路径的服务质量确保策略被提出来,它建立了一个连续QoS监测模型,以路径响应延迟为核心度量标准,将同一类应用抽象为一条虚拟路径,并以路径黏合起系统的各个组件。同时据此提出了一套动态自适应的QoS监控算法。测试表明,即使经历严重的过载与业务突发,也能保证用户感知的服务质量。     

Algorithm Validation of the Current Profile Reconstruction of EAST Based on Polarimeter/Interferometer

The method of plasma current profile reconstruction using the polarimeter/interferometer(POINT) data from a simulated equilibrium is explored and validated.It is shown that the safety factor(q) profile can be generally reconstructed from the external magnetic and POINT data.The reconstructed q profile is found to reasonably agree with the initial equilibriums.Comparisons of reconstructed q and density profiles using the magnetic data and the POINT data with 3%,5%and 10%random errors are investigated.The result shows that the POINT data could be used to a reasonably accurate determination of the q profile.     

Experimental observation of reverse- sheared Alfvén eigenmodes (RSAEs) in ELMy H-mode plasma on the EAST tokamak

Reverse-sheared Alfvén eigenmodes (RSAEs) have been observed by using an interferometer and ECE diagnostics in NBI heated ELMy H-mode plasma on EAST tokamak. A typical feature of these modes is a fast frequency sweeping upward from ∼80 kHz to ∼110 kHz in hundred milliseconds during which the plasma temperature, density and rotation keeps no change. Only core channels of the interferometer can observe these modes, implying a core localized mode. The ECE measurement further showed that these modes located at about ρ=0.37–0.46, just around the position of q_min with ρ∼0.4. These core localized modes are very weak in the magnetic fluctuations measured by mirnov probes mounted at the machine vacuum vessel. A multiple frequency fluctuation component, seemingly the so-called ‘grand cascades’, was also clearly observed on the ECE signal at ρ=0.46. During the phase, a transient internal transport barrier (ITB) in ion temperature and toroidal rotation was observed and the ITB foot was just close to the position of q_min . A modulation of RSAE frequency by ELM event was observed and this modulation could be attributed to rotation decrease orq_min increase due to ELM. Further study of these modes in EAST can provide valuable constraints for the q profile measurement and will be important for the long pulse operation.     

离子回旋频率波加热下的EAST等离子体锯齿行为研究

利用软X射线、中子注量检测诊断系统和偏振干涉仪（Polarimeter-interferometer,POINT）约束下的平衡反演算法（Equilibrium Fitting Algorithm,EFIT）,对东方超环（Experimental Superconducting Tokamak,EAST）等离子体在离子回旋共振频率波（Ion Cyclotron Resonance Frequency wave,ICRF）在轴沉积加热下的锯齿周期,锯齿幅度,q=1面处等离子体压强梯度,q=1面的半径的变化情形进行了研究。研究发现,在轴沉积情况下,加入ICRF可以对锯齿起致稳作用（延长锯齿周期）,锯齿周期与ICRF功率呈正相关;锯齿周期随着ICRF的加入或者ICRF功率的变化趋势,与锯齿幅度和q=1面处等离子体压强梯度变化趋势大体上一致;要改变q=1面半径,ICRF的功率可能需要到0.8 MW以上;在ICRF功率占比更高的加热条件下,锯齿周期和q=1面半径随着ICRF功率变化更敏感;EAST中ICRF产生的快离子和导致的q=1面半径的变化可能对锯齿行为有一定的影响。