SUNIST装置中磁探针出气率测量

通过出气率测量装置评价了SUNIST装置的内部磁探针出气特性,实验结果表明其出气量和出气气体成分不足以影响SUNIST真空特性。其后的放电实验验证了这一结论。     

Effect of Elongation on Critical Gradient for Toroidal Electron Temperature Gradient Modes

The electron temperature gradient mode is investigated in elongated toroidal plasmas with a gyrokinetic integral eigenmode equation code. Dependence of the critical electron temperature gradient on the elongation is calculated. It is found that when the elongation increases, the growth rate spectrum is greatly shifted towards shorter poloidal wavelength, and then the poloidal wavenumber at which the mode is destabilizing critically in elongated plasmas will be larger than that in circular plasmas.     

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通过出气率测量装置评价了SUNIST装置的内部磁探针出气特性,实验结果表明其出气量和出气气体成分不足以影响SUNIST真空特性。其后的放电实验验证了这一结论。     

Observation of Radial Propagation of Electrostatic Fluctuations in Edge Plasma of the Sino United Spherical Tokamak

Radial propagation of electrostatic fluctuations in the edge plasma of Sino-United Spherical Tokamak (SUNIST) has been measured using Langmuir probes. The propagation characteristics of the floating potential fluctuations are analysed by the two-point correlation technique. The results show radially outward propagation of the turbulent fluctuations at all measured radial positions. The power-average wavenumber profile is approximately constant in plasma edge region and suddenly increases to the limiter. These results are in good agreement with the model predictions proposed by Mattor which suggests that the drift wave propagation may be a source of edge turbulence.     

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介绍了在SUNIST装置上进行的ECW辅助欧姆感应电流启动实验。在ECW(2.45GHz/20kW/10ms)和垂直场感应的共同作用下,先驱动起一个较小的等离子体电流(<1kA),再投入欧姆场,可以获得比常规欧姆放电更高的电流爬升速率,提高伏秒数的利用效率。这种启动方式为SUNIST欧姆放电提高了灵活性,可以在不进行硬件改动的前提下增加调节等离子体平衡的余量,拉长放电的持续时间。     

A New Kinetic Mode Driven by Electron Temperature Gradient

A new unstable short wavelength mode is identified in sheared slab plasmas using a fully kinetic integral equation code. This mode is driven by the electron temperature gradient and propagates in the ion diamagnetic direction. The instability occurs due to the electron inverse Landau damping effect at short cross-field wavelength regions.     

中国联合球形托卡马克氦放电等离子体的碰撞辐射模型及其在谱线比法诊断的应用

介绍了针对中国联合球形托卡马克氦放电等离子体建立的碰撞辐射(CR)模型.给出CR模型计算的来自主量子数n=4激发态能级的三条谱线的强度比447.1 nm(23P—43S)/492.2 nm(21P—41D)和492.2 nm/504.8 nm(21P—41S)在电子温度Te和电子密度Ne空间内的计算结果.建立了根据谱线强度比确定Te与Ne的谱线比法.将该方法应用在氦放电等离子体诊断上,通过与微波干涉仪测量结果的对比以及CR模型与实验测量的激发态数密度的对比验证了方法的有效性.分析了引起诊断结果误差的因素,包括实验测量设备误差、CR模型使用的速率系数不确定度与能级选取,以及光谱测量的弦积分特性等.     

针对神光II升级装置的直接驱动快点火集成实验靶的初步设计

神光II激光装置升级完成后,激光能量将大幅提高,同时配备皮秒拍瓦激光束,能够满足快点火研究在万焦耳级平台开展集成实验的需求.神光II升级装置设计原则是以间接驱动为主,兼顾直接驱动.尽管直接驱动只是替代方案,然而由于直接驱动在快点火预压缩中具备一定优势,如能量利用率较高、对快点火导引锥预热较少、便于诊断等,因此需要探索基于神光II升级装置的直接驱动快点火靶设计.本文针对神光II升级装置的激光条件,利用辐射流体程序Multi1D对集成实验用快点火直接驱动靶的尺寸进行了初步内爆压缩设计和优化.在激光条件固定的情况下,优化无充气单层靶球的半径、厚度,尽可能实现高的密度、面密度.得到最优靶参数为外半径420μm,壳层厚度35μm,与靶球定标关系验证一致.根据超热电子定标关系,计算表明压缩过程实现的最高面密度与皮秒拍瓦激光产生的超热电子射程基本匹配.     

Short Wavelength Ion Temperature Gradient Driven Instability in Noncircular Flux Surface Plasmas with Finite Aspect Ratio

By employing the local equilibrium of shaped tokamak plasmas, a gyrokinetic model with integral eigenmode equations is developed to investigate effects of the finite aspect ratio and noncircular flux surface on short wavelength ion temperature gradient （SWITG） driven modes. It is found that when nonadiabatic electron and trapped particle effects are not considered, the SWITG mode can be stabilized by finite aspect ratio A, elongation and triangularity δ, and can be destabilized by the Shafranov shift gradient θRo/θr.     

反常电子粘滞性引起的线性双撕裂模研究

用圆柱位形的磁流体动力学方程对由反常电子粘滞性引起的双撕裂模的线性行为做了数值研究.分析了两个有理面的间距、粘滞率大小和极向模数对双撕裂模模式结构的影响,给出了各种情况下双撕裂模线性增长率跟表征反常电子粘滞率大小的电子雷诺数的定标关系.