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本文报道了测量CT—6托卡马克二次谐波非寻常模的电子回旋辐射的实验结果及局部等离子体的电子温度Te随时间变化。通过改变装置纵场B_T值得到Te的空间分布。与硬X射线测量比较,确定了CT-6装置在电流上升阶段经常出现的逃逸电子辐射现象。本文也给出了实验中所观察到的等离子体内部MHD不稳定性所引起的辐射锯齿形扰动。 相似文献
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采用相关分析法模拟分析了HL-1M装置的磁扰动模式,模拟的结果同预期的结果一致。在具有磁流体不稳定性的典型放电中,探测到独立模m=2、3、4,耦合模m=2、3,以及同时出现的耦合模m=4、5和独立模m=5,给出了用扰动幅度的极向截面图分析磁扰动模式的结果,讨论了相关分析法在实验分析中的优点和局限性。 相似文献
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CT-6是我国第一台托卡马克装置,于1974年在中国科学院物理研究所建成.CT-6B是其在1978年的升级版,于2000年关闭.我们主要叙述它们早期的历史. 相似文献
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《物理学报》1980,(5)
托卡马克是一种产生高温环形等离子体的聚变实验装置,也是一类复杂的现代化的电物理装备。CT-6是我国首先投入运行的小型托卡马克装置,其主要参数为:大半径45cm;小半径9.2cm;环向磁场2TL;等离子电流30kA;经过调试阶段,达到了预期目标,产生了平衡、稳定的电子温度为250eV左右的环形高温等离子体。CT-6由电磁系统(包括环向场、涡旋场、平衡场)、超高真空系统(包括环形真空室和抽气机组)、电源控制系统和诊断测量系统等部份组成,它是由中国科学院物理研究所、电工研究所及其他许多单位协作研制成功的。 本文描述CT-6装置的设计、结构、工程研制和调试过程,以及有关的试验结果。 相似文献
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The inward propagation equation of heat wave driven by a weak alternating modulation of the toroidal plasma curent in a tokamak plasma has been exactly solved. Based on this solution, an ac-tive method to determine the electron thermal conduction in a tokamak plasma has been proposed. The thermal conductivity is calculated as a function of minor radius From the soil X-ray data obtained in experiments on thc CT-6B Tokamak. Thc results indicate the anornalous feature of the electron thermal conduction. 相似文献
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Voshall R. E. Wright R. J. Liebermann R. W. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1977,5(2):110-122
A closed-cycle MHD generator topping a steam bottoming plant is analyzed. The combined power plant involves three working fluids in three loops. The MHD loop is investigated more thoroughly since it is the least conventional of the three. Equations are developed to determine the geometric and thermodynamic variables throughout the MHD channel for inlet conditions of mass flow, temperature, pressure, and velocity. Limiting design parameters are output power, channel length, channel aspect ratio, Hall parameter, and interaction parameter. The basic closed-cycle MHD loop working fluid can consist of either argon or helium seeded with cesium. Both non-equilibrium ionization produced by the elevation of the electron temperature from joule heating of the plasma and thermal ionization are considered. Equations used to calculate the electrical conductivity and the elevation of electron temperatures are derived. These equations are coupled with the one-dimentional differential equations applicable to an MHD generator. The chief interest is in determining those MHD channel conditions which result in the most thermodynamically efficient MHD-steam plantcombination. Thus an overall heat balance forthe system is required. Equations are developed to calculate the gas properties at the various stations of the closed loop and to determine the overall efficiency of the cycle. A rather flexible computer program written in Fortran is used to solve the MHD generator equations and to make the overall heat balance. Some typical results presented demonstrate the feasibility and adaptability of the analysis for optimizing the thermal efficiency and the sensitivity of thermal efficiency to various parameters. 相似文献
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一、基本方程与计算方法 1.锯齿模式锯齿上升部分可做如下解释,焦耳加热使电流分布变尖,q减小,致使m=1的撕裂模变得不稳定,磁岛将增长。r_s是q=1处的半径,由下式给出 q(r_s)=1. (1) 磁岛宽度由给出。式中W_o为初值,Y是m=1/n=1模的线性增长率 相似文献
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Effects of variable properties on MHD heat and mass transfer flow near a stagnation point towards a stretching sheet in a porous medium with thermal radiation
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The effect of variable viscosity and thermal conductivity on steady magnetohydrodynamic(MHD) heat and mass transfer flow of viscous and incompressible fluid near a stagnation point towards a permeable stretching sheet embedded in a porous medium are presented,taking into account thermal radiation and internal heat genberation/absorbtion.The stretching velocity and the ambient fluid velocity are assumed to vary linearly with the distance from the stagnation point.The Rosseland approximation is used to describe the radiative heat flux in the energy equation.The governing fundamental equations are first transformed into a system of ordinary differential equations using a scaling group of transformations and are solved numerically by using the fourth-order Rung-Kutta method with the shooting technique.A comparison with previously published work has been carried out and the results are found to be in good agreement.The results are analyzed for the effect of different physical parameters,such as the variable viscosity and thermal conductivity,the ratio of free stream velocity to stretching velocity,the magnetic field,the porosity,the radiation and suction/injection on the flow,and the heat and mass transfer characteristics.The results indicate that the inclusion of variable viscosity and thermal conductivity into the fluids of light and medium molecular weight is able to change the boundary-layer behavior for all values of the velocity ratio parameter λ except for λ = 1.In addition,the imposition of fluid suction increases both the rate of heat and mass transfer,whereas fluid injection shows the opposite effect. 相似文献
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本文解析研究了电阻性互换不稳定性的湍性行为和它所引起的电子热传导及其所带来的场反向箍缩能量约束性能下降的情形。对于两种不同的模宇称计算了磁场饱和涨落水平,并由此求得了磁颤动扩散系数及碰撞区、非碰撞区的热传导系数。得到了能量约束时间的定标律。
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Injection of high-Z impurities into plasma has been proved
to be able to reduce the localized thermal load and mechanical forces on
the in-vessel components and the vacuum vessel, caused by
disruptions in Tokamaks. An advanced prediction and mitigation
system of disruption is implemented in HL-2A to safely shut down
plasmas by using the laser ablation of high-Z impurities with a
perturbation real-time measuring and processing system. The
injection is usually triggered by the amplitude and frequency of
the MHD perturbation field which is detected with a Mirnov coil and leads
to the onset of a mitigated disruption within a few milliseconds. It
could be a simple and potential approach to significantly reducing the
plasma thermal energy and magnetic energy before a disruption,
thereby achieving safe plasma termination. The plasma
response to impurity injection, a mechanism for improving plasma
thermal and current quench in major disruptions, the design of
the disruption prediction warner, and an evaluation of the mitigation success rate
are discussed in the present paper. 相似文献
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In this study, the effects of variable fluid properties on heat transfer in MHD Casson fluid melts over a moving surface in a porous medium in the presence of the radiation are examined. The relevant similarity transformations are used to reduce the governing equations into a system of highly nonlinear ordinary differential equations and those are then solved numerically using the Runge–Kutta–Fehlbergmethod. The effects of different controlling parameters, namely, the Casson parameter,melting and radiation parameters, Prandtl number,magnetic field, porosity, viscosity and the thermal conductivity parameters on flow and heat transfer are investigated. The numerical results for the dimensionless velocity and temperature as well as friction factor and reducedNusselt number are presented graphically and discussed. It is found that the rate of heat transfer increases as the Casson parameter increases. 相似文献
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对于种子干燥方面的研究,大多是针对其宏观传热传质即干燥动力学方面。本文采用热成象技术对单颗蚕豆种子的传热过程进行了研究,用实验求解导热方程反问题的方法计算出不同含水率下单颗种子的导热系数,对种子在非稳态下内部温度场进行了测试与分析.研究结果表明,在含水率小于 20%时,其导热系数随着含水率的增加而增大,当含水率大于 25%时则表现出较强的非均质性和非稳态性。对单颗蚕豆种子内部温度场测定而得到的种子热剖面温度分布表明,种子内部存在温度梯度其热扩散具有均匀性,同时反映出种皮传热热阻的存在。这些结果对于深入研究种子内部的传热传质机理,具有重要的实际意义。 相似文献