H-mode confinement of Heliotron J-猫眼课题宝

DOI：

10.1088/0029-5515/45/12/011

发表时间：

2005-11

期刊：

Nuclear Fusion

影响因子：

3.3

通讯作者：

中科院分区：

物理与天体物理1区

文献类型：

作者：

F. Sano;T. Mizuuchi;K. Kondo;K. Nagasaki;H. Okada;S. Kobayashi;K. Hanatani;Y. Nakamura;S. Yamamoto;Y. Torii;Y. Suzuki;H. Shidara;M. Kaneko;H. Arimoto;T. Azuma;J. Arakawa;K. Ohashi;M. Kikutake;N. Shimazaki;T. Hamagami;G. Motojima;H. Yamazaki;M. Yamada;H. Kitagawa;T. Tsuji;H. Nakamura;S. Watanabe;S. Murakami;N. Nishino;M. Yokoyama;Y. Ijiri;T. Senju;K. Yaguchi;K. Sakamoto;K. Tohshi;M. Shibano

研究了螺旋轴heliotron J中的L-H跃迁。对于电子回旋加热（ECH）、中性束注入加热（NBI）和ECH + NBI组合加热等离子体，研究了h模式的约束质量，重点研究了其磁组态的依赖性。真空边缘旋转变换，ι(a)/2π，被选择作为磁性结构的标记，其中ι/2π是旋转变换，a是平均等离子体小半径，单位为米。实验中，增强因子对l模约束的ι(a)/2π依赖性表明，存在特定的构型，可以获得高质量的h模（1.3 < HISS95 < 1.8）。为实验全球能量约束时间，为来自国际仿星器数据库的约束时间标度，为。R是等离子体的主半径，单位为米；是等离子体的线平均密度，单位为1019 m−3；PL是功率损耗，单位为兆瓦，它表示等离子体总能量含量的时间导数；Bt是环形磁场强度，单位为特斯拉（Stroth U. et al . 1996 nuclear）。Fusion 36 1063)。这些构型的ι (a)/2π范围接近于Heliotron J的主要自然共振值，即n/m = 4/ 8,4 /7和12/22。为了更好地理解这种构型依赖性，我们计算了不同ι(a)/2π值下的几何极向粘性阻尼率系数Cp，并与实验结果进行了比较。在ECH (0.29 MW) + NBI （0.57 MW）模式下，h模式的阈值线平均密度在0.7-2.0 × 1019 m−3之间，这取决于配置。至于边缘等离子体的特性，Langmuir探针的测量结果显示，在最后一个封闭通量面（LCFS）内部开始并延伸到刮擦层的区域，波动引起的输运减少了。此外，在过渡时，在LCFS附近同时形成负的径向电场Er（或Er-shear）。

The L–H transition in a helical-axis heliotron, Heliotron J, is investigated. For electron cyclotron heating (ECH), neutral beam injection (NBI) heating and ECH + NBI combination heating plasmas, the confinement quality of the H-mode is examined with an emphasis on its magnetic configuration dependence. The vacuum edge rotational transform, ι(a)/2π, is chosen as a label for the magnetic configuration where ι/2π is the rotational transform and a is the average plasma minor radius in metres. The experimental ι(a)/2π dependence of the enhancement factor over the L-mode confinement reveals that specific configurations exist where high-quality H-modes (1.3 < HISS95 < 1.8) are attained. is the experimental global energy confinement time and is the confinement time scaling from the international stellarator database given as . R is the plasma major radius in metres, is the line-averaged plasma density in 1019 m−3, PL is the power loss in megawatts that accounts for the time derivative of the total plasma energy content and Bt is the toroidal magnetic field strength in tesla (Stroth U. et al 1996 Nucl. Fusion 36 1063). The ι (a)/2π ranges for these configurations are near values that are slightly less than those of the major natural resonances of Heliotron J, i.e. n/m = 4/8, 4/7 and 12/22. To better understand this configuration dependence, the geometrical poloidal viscous damping rate coefficient, Cp, is calculated for different values of ι(a)/2π and compared with the experimental results. The threshold line-averaged density of the H-mode, which depends on the configuration, is in the region of 0.7–2.0 × 1019 m−3 in ECH (0.29 MW) + NBI (0.57 MW) operation. As for the edge plasma characteristics, Langmuir probe measurements have shown a reduced fluctuation-induced transport in the region that begins inside the last closed flux surface (LCFS) and extends into the scrape-off layer. In addition, a negative radial electric field Er (or Er-shear) is simultaneously formed near the LCFS at the transition.

H-mode confinement of Heliotron J

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