共查询到20条相似文献,搜索用时 9 毫秒
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Volodymyr Makhin Bruno S. Bauer Thomas J. Awe Stephan Fuelling Tasha Goodrich Irvin R. Lindemuth Richard E. Siemon Sergei F. Garanin 《Journal of Fusion Energy》2007,26(1-2):109-112
A possible plasma target for Magnetized Target Fusion (MTF) is a stable diffuse z-pinch in a toroidal cavity, like that in
MAGO experiments. To examine key phenomena of such MTF systems, a magnetic flux compression experiment with this geometry
is under design. The experiment is modeled with 3 codes: a slug model, the 1D Lagrangian RAVEN code, and the 1D or 2D Eulerian
Magneto-Hydro-Radiative-Dynamics-Research (MHRDR) MHD simulation. Even without injection of plasma, high-Z wall plasma is generated by eddy-current Ohmic heating from MG fields. A significant fraction of the available liner kinetic
energy goes into Ohmic heating and compression of liner and central-core material. Despite these losses, efficiency of liner
compression, expressed as compressed magnetic energy relative to liner kinetic energy, can be close to 50%. With initial fluctuations
(1%) imposed on the liner and central conductor density, 2D modeling manifests liner intrusions, caused by the m = 0 Rayleigh-Taylor instability during liner deceleration, and central conductor distortions, caused by the m = 0 curvature-driven MHD instability. At many locations, these modes reduce the gap between the liner and the central core
by about a factor of two, to of order 1 mm, at the time of peak magnetic field. 相似文献
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T. J. Awe R. E. Siemon B. S. Bauer S. Fuelling V. Makhin S. C. Hsu T. P. Intrator 《Journal of Fusion Energy》2007,26(1-2):17-20
Two codes have been developed to model solid metal or wire-wound conductors. The calculations are based on the decomposition
of the conductors into arrays of thin wires. The first code, EDDY, models cylindrically symmetric conductors with currents
in the theta direction. This code accurately models eddy current induction and magnetic diffusion. It was created in order
to aid the design of magnetic-field shields in the FRX-L experiment for Magnetized Target Fusion (MTF). EDDY uses fast, accurate
elliptic integral subroutines from MATLAB to solve for the time-dependent current flowing through each wire loop and the resultant
magnetic field configuration. The second code, INDIV, models arbitrarily shaped conductors with current flow in the z direction. It was designed to model current division in an inductive divider that would inject current into a liner cavity,
for magnetic flux and magnetized-plasma compression experiments. An experiment has been performed to test the INDIV code and
the inductive division concept. The numerical results compare well with those of the experiment. 相似文献
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Electrostatic helicity injection involves the injection of new azimuthal magnetic flux to link the existing axial flux of
an open magnetic field. Since magnetic flux is frozen into plasma, this injection of new flux requires the injection of new
plasma as well. This associated plasma injection means that helicity injection involves an increase of the density in the
flux tube comprised by the initial open magnetic field lines. The injection of plasma and its embedded magnetic flux results
in a collimation of the open flux tube when the embedded magnetic flux becomes compressed due to flow stagnation. Plasma injection
occurs in the form of jets originating from biased electrodes having plasma sources. These jets can originate from both cathodes
and anodes. An ion orbit instability may occur for cathode-originating jets. In cathode-originating jets the ions move opposite
to the direction of the conventional current and so experience an anti-pinch force which can be strong enough to overwhelm
the usual magnetic force responsible for cyclotron orbit motion. 相似文献
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John Slough Samuel Andreason Hiroshi Gota Chris Pihl George Votroubek 《Journal of Fusion Energy》2007,26(1-2):199-205
An experimental program has been initiated that will explore the very compact, high energy density regime of fusion based
on the magneto-kinetic compression of the FRC. Of all fusion reactor embodiments, only the FRC has the simply-connected closed
field, linear confinement geometry, and intrinsic high β required for magnetic fusion at high energy density. PHD takes advantage
of the linear confining geometry by incorporating a traveling, burning plasmoid, significantly reducing the wall loading as
well as keeping the formation well separated from the burn chamber. Being small, compact, and at high β greatly improves the
exposed surface to reacting volume ratio. Being pulsed eliminates the need for flux sustainment, and provides for regulation
of the average wall loading. A wide range of reactor scenarios are compatible with PHD including liquid metal walls with the
prospect of direct energy conversion through cyclical wall compression/expansion. 相似文献
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《等离子体科学和技术》2016,18(7):714-719
A flux difference splitting numerical scheme based on the finite volume method is applied to study ideal/resistive magnetohydrodynamics. The ideal/resistive MHD equations are cast as a set of hyperbolic conservation laws, and we develop a numerical capability to solve the weak solutions of these hyperbolic conservation laws by combining a multi-state Harten-Lax-Van Leer approximate Riemann solver with the hyperbolic divergence cleaning technique, high order shock-capturing reconstruction schemes, and a third order total variance diminishing Runge-Kutta time evolving scheme. The developed simulation code is applied to study the long time nonlinear evolution of the coalescence instability. It is verified that small structures in the instability oscillate with time and then merge into medium structures in a coherent manner. The medium structures then evolve and merge into large structures, and this trend continues through all scale-lengths.The physics of this interesting nonlinear dynamics is numerically analyzed. 相似文献
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为满足脉冲中子探测系统对辐射屏蔽的要求,在利用MCNP程序模拟计算准直孔分别为圆柱形直孔和锥形孔的屏蔽效果基础上,设计了圆柱形直孔+锥形孔的准直器结构,准直器采用铁35cm厚+聚乙烯20 cm厚+铅15 cm厚的组合材料。理论计算表明:该准直器用于反冲质子探测系统时,探测系统输出信号与干扰信号的比值大于10。 相似文献
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本文对卧式V型管高压汽水两相流的传热特性进行了试验研究。根据试验得到了计算临界热负荷的关系式。该式可用来预测卧式V型管弯头上、下游部分的传热恶化条件,为沸腾燃烧锅炉中卧式V型坦管、锅炉炉膛出口凝渣管等的设计与运行提供了可靠依据。 相似文献
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发生失水事故后的压水堆内会产生池式夹带现象,这一现象将造成反应堆进一步失水,进而发生堆芯裸露或堆芯熔化等严重事故。Kataoka和Ishii于1983年开发的池式夹带模型在反应堆安全分析中被广泛使用,但十分保守。其中一个重要原因是模型中高速夹带区的试验数据极为有限且不确定性较大,导致该区的模型并不完善。本文介绍空气-水的池式夹带高速区试验,试验本体参考AP1000原型参数,本体内径为380 mm,高为2.2 m,由透明材料制作,供气流速为0.98~5.41 m/s。试验过程中的两相混合液位和夹带液体质量的测量分别使用导波雷达液位计和称重模块。本试验为夹带模型的高速区补充了数据,发展了现有的池式夹带高速区模型,并发现了在夹带高速区出现的夹带饱和现象。 相似文献
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采用R134a作为流体工质,对单棒垂直方形通道临界热流密度(CHF)进行了实验研究。流道横截面为19 mm×19 mm的方形通道,内置外径为9.5 mm的单根加热棒,用来模拟压水堆中典型栅元通道。实验工况通过流体模化方法覆盖了压水堆典型运行工况。实验结果表明,R134a在方形通道内的CHF参数趋势与圆管中水的CHF参数趋势相同,R134a可以替代水作为模化工质;通过对圆管Bowring关系式和Katto & Ohno关系式进行冷壁因子修正,可用于预测带有冷壁的方形通道的CHF;Katto的流体模化方法适用于带有冷壁的方形通道。 相似文献
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在ATLAS TDAQ框架的基础上,为暗物质实验开发了基于网络读出的数据获取软件。软件实现了高速数据读出,事例组装,数据波形零压缩和存盘等功能。论文最后对软件的运行情况进行了稳定性测试,软件的读出带宽可达到240MB/s,波形压缩比可达到150倍。 相似文献
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《Journal of Nuclear Science and Technology》2013,50(8):792-798
The erosion of pyrolytic graphite and titanium doped graphite RG-Ti above 1,780K was investigated by 5keV Ar beam irradiation with the flux from 4x1019 to 1x1021 m?2·s?1. The total erosion yields were significantly reduced with the flux. This reduction would be attributed to the reduction of RES (radiation enhanced sublimation) yield, which was observed in the case of isotropic graphite with the flux dependence of RES yield of φ?0.26 (φ: flux) obtained in our previous work. The yield of pyrolytic graphite was roughly 30% higher than that of isotropic graphite below the flux of 1020 m?2·s?1 whereas each yield approached to very close value at the highest flux of 1x1021 m?2·s?1. This result indicated that the effect of graphite structure on the RES yield, which was apparent in the low flux region, would disappear in the high flux region probably due to the disordering of crystal structure. In the case of irradiation to RG-Ti at 1,780K, the surface undulations evolved with a mean height of about 3μm at 1.2×1020 m?2·s?1, while at higher flux of 8.0×1020 m?2·s?1 they were unrecognizable. These phenomena can be explained by the reduction of RES of graphite parts excluding Tic grains. 相似文献
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A magnetic measurement system consisting of magnetic probes and flux loops for spherical tokamak SUNIST, is uniquely designed due to the strongly shaped plasma cross section and the narrow space near the central solenoid. Plasma equilibrium reconstruction with the current filament method is performed to determine the number and positions of the magnetic probes and flux loops, as well as their design precision required. 相似文献
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介绍了核工业西南物理研究院聚变实验增殖堆工程概要设计(FEB-E)中的氚系统设计研究。第一部分介绍包层氚增殖区的划分、几何尺寸、装料特征和用蒙特卡罗程序计算得到的液态锂中的氚浓度分布;第二部分描述根据聚变堆氚物理基础构造的氚循环系统,共分成 10 个子系统及它们之间氚的流程图。运用研制的程序SWITRIM 计算了各个子系统中的氚投料量随时间的变化,满功率运行一年后各个子系统中的氚投料量。研究结果表明起动 143 MW 聚变功率 FEB-E 堆所需要的初始氚投料量大约为 319 g。第三部分对不同的运行状态下的氚泄漏问题进行了分析。潜在的氚泄漏危险可能来自于偏滤器系统从等离子体中抽出的气体。得到的结论是提高FEB-E 堆芯等离子体的燃耗份额从而减少氚的通过量对降低氚的泄漏危险是重要的。 相似文献