共查询到18条相似文献,搜索用时 109 毫秒
1.
耿大革 《核聚变与等离子体物理》1985,(1)
通过氢气击穿实验从数量级上推算了预试环(一个无铜壳的小托卡马克装置)的垂直杂散场。结果符合于按环向场绕组的过渡线和补偿回线的汁算值以及用磁探针对加热场杂散场的测量值。 相似文献
2.
为了模拟GBH-1装置的垂直场形态,用低电压电容器组和快速可控硅做开关,对GBH-1的模型线圈放电,它比同类实验更简化。测量了磁场形态和电流分布,并研究了在GBH-1装置中引入成形场线圈的方案。 相似文献
3.
在分析星地链路几何结构及传播模型的基础上,研究基于联合代数重建技术的星地链路反演二维垂直降雨场的方法.利用实测降雨资料构建3类降雨场,并搭建3条17 GHz垂直极化星地链路进行数值仿真.实验结果表明:单星地链路无法实现二维垂直降雨场的重构,反演场与真实场的相关系数分别为0.556,0.504和0.364;基于双星地链路的反演结果和真实场的相关系数均高于0.98,平均偏差分别为0.122, 0.159和0.537 mm/h,欧式距离均低于0.9 mm/h,熵的相对误差均小于1.6%,基本实现了二维垂直降雨场的反演;三星地链路的应用进一步提升了反演精度,相关系数接近于1,能够精准重构降雨场.实验结果验证了基于星地链路的垂直降雨场反演方法的可行性、准确性和有效性.星地链路的架设和维护简单,探测降雨范围广,易于在高原、山区、海岛等传统地面观测资料缺失的地区使用,可以作为已有降水测量手段的补充. 相似文献
4.
5.
HL—1装置等离子体位置反馈控制 总被引:2,自引:2,他引:0
本文简述了用位移做反馈控制信号,用非线性二位调节器组合前馈环节,控制厚钢壳(厚度d=5cm)外的垂直场和水平场线圈电流,在HL-1装置上实现了等离子体位置反馈控制的情况。当铁芯不饱和时,在水平和垂直两个方向上均可控制等离子体位置在±2mm之内。 相似文献
6.
7.
HL-1装置等离子体平衡的实验研究 总被引:3,自引:3,他引:0
用对称磁探针测量了HL-1装置等离子体环的水平位移和垂直位移,经微机数据处理系统即时给出了位移随时间的变化曲线,并对装置的杂散场情况作了讨论。实验表明,平衡场和杂散垂直场的合成场能保证等离子体平衡在孔栏中心附近的位置。 相似文献
8.
本文介绍一个计算轴对称任意截面环形等离子体平衡问题的方法。先选定等离子体边界和环电流分布,用有限元方法解平衡方程的边值问题。借助于虚壳原理,得到用平衡方程解表示的能够产生平衡时所需要的维持场的虚壳电流。计算虚壳电流在等离子体区的维持场,以它为根据,采用积分方程开拓,求等离子体区外某位形上的维持场电流分布。解决这个问题的主要困难是当磁场向外开拓时遇到了不适定问题。我们用奇异值分解方法解不适定的Fredholm第一类积分方程。这个方法能容易地找到稳定解,对解决这个平衡问题是简单有效的。我们以七种等离子体截面形状,三种电流分布为具体模型,在三种维持场电流分布位形上给出了维持场电流分布。还给出了维持场形态,维持场总电流与等离子体总电流的比较,并简单讨论了维持场对等离子体整体稳定性的影响。
关键词: 相似文献
9.
本文叙述了HL-1装置环向场线圈、内外垂直场线圈,欧姆变压器初级绕组和偏磁绕组的磁场测量方法和结果,初步讨论了带有切口的铜壳对磁场的影响。 相似文献
10.
葛袁静 《核聚变与等离子体物理》1985,(3)
本文叙述了HT-6A托卡马克平衡系统及第一期平衡实验结果.讨论了HT-6A上铜壳对平衡的贡献;观察到改变垂直场形态因子n而产生的水平位移及垂直位移不稳定现象;介绍了正常放电时的平衡实验,观察到等离子体位移与MHD扰动是紧密相连的;用沙弗拉诺夫薄壳理论计算了对多大的等离子体电流应施加多大的垂直场,结果与实验完全符合。 相似文献
11.
铜壳涡流磁场的实验研究 总被引:1,自引:1,他引:0
本文介绍了模拟等离子体电流环电流在HL-1装置铜壳的1/4段上感应的涡流,在等离子体区产生的磁场大小、分布和时间特征的测量结果.涡流产生的垂直场随着等离子体电流环水平位移和电流上升率的增加而增加,而且在空间各点的大小和衰减时间常数都不相同。极向缝隙使涡流产生的垂直场和水平场沿大环方向呈周期性变化,环向缝隙对垂直场没有影响,但是却大大减弱了涡流产生的水平场。 相似文献
12.
The purpose of this study was to analyse the relationship between the radio frequency (RF) coil performance and conductor surface shape for ultra-high field (UHF) magnetic resonance imaging. Twelve different leg-shaped quadrature birdcage coils were modeled and built, e.g., 4 mm-width-leg conventional birdcage coil, 7 mm-width-leg conventional birdcage, 10 mm-width-leg conventional birdcage coil, 13 mm-width-leg conventional birdcage coil, inside arc-shape-leg birdcage coil, outward arc-shape-leg birdcage coil, inside right angle-shape-leg birdcage coil, outward right angle-shape-leg birdcage coil, vertical 4 mm-width-leg vertical birdcage, 6 mm-width-leg vertical birdcage, 8 mm-width-leg vertical birdcage and 10 mm-width-leg vertical birdcage. Studies were carried out in both electromagnetic simulations with finite element method as well as in vitro saline phantom experiments at 9.4 T. Both the results of simulation and experiment showed that conventional birdcage coil produces the highest signal-to-noise ratio (SNR) while the vertical birdcage coil produces the most homogeneous RF magnetic (B 1) field at UHF. For conventional birdcage coils, as well as the vertical birdcage coils, only the proper width of legs results in the best performance (e.g., B 1 homogeneous and SNR). For vertical birdcage coils, the wider the leg size, the higher RF magnetic (B 1) field intensity distribution. 相似文献
13.
Castle G.G. Wootton A.J. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1994,22(4):369-375
To determine whether or not magnetic field lines inside a tokamak plasma are stochastic we need the Fourier coefficients of any perturbing radial field inside the plasma. Usually what is measured with magnetic pick-up coils is the root mean square poloidal field outside the plasma. Although no unique transformation is available, we present a model which allows an interpretation of the measured (external) root mean square field in terms of the internal Fourier harmonics. The results are applied to particular TEXT discharges, and suggest a link between magnetic stochasticity and an increasing (more positive) radial electric field, as measured with a heavy ion beam probe 相似文献
14.
15.
HE Yuan XIONG Hui LIU Wei-Jun HAN Shao-Fei YUAN Ping MA Li-Zhen ZHANG Bin WANG Wen-Jin WANG Yue XIA Jia-Wen 《中国物理C(英文版)》2003,27(6):532-536
The trimming coils embedded in poles of magnet are applied in the C-dipole prototypes of CSR. They are used to adjust the uniformity of magnetic fields through reducing outside magnetic field and augmenting inside. The impact of trimming currents on the uniformity of field and multipole components is carefully investigated by using the two kinds of magnetic measurements,hall sensor and long coil,respectively. It is proved that the uniformity which is better than ±1.0×10 -3 can be reached easily. At the same time,the quadrupole and sextupole components of fields have decreased to a low level through optimizing the trimming currents,but,unfortunately,the octupole and dodecapole will increase correspondingly. Finally,the two measured and calculated results are compared. There is very small difference between the results of the two measuring methods. However,all of the measured results are alien to the calculated one because of the insufficiency of the TOSCA calculation. 相似文献
16.
Geoffrion J. Gregory B.C. Couture P. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1988,16(3):393-395
A virtual movement of the plasma in the radial direction was studied in order to obtain the magnitude of the vertical field applied to the Tokamak de Varennes plasma for fast horizontal motion using coils inside the vacuum vessel. The developed model includes the radial dependence of several parameters 相似文献
17.
SUNIST低环径比托卡马克的供电系统 总被引:1,自引:1,他引:0
介绍了SUNIST低环径比托卡马克的纵向场线圈、欧姆加热场线圈和平衡场线圈的电学参数。所用电容器组储能系统采用电容换流式准恒流充电回路。测量了这三组线圈中的放电电流,并将测量结果与回路计算结果作了比较。 相似文献