搜索

x
中国物理学会期刊

HL-2A托卡马克电子回旋共振加热调制对湍流驱动和传播的影响

CSTR: 32037.14.aps.74.20241263

Effects of electron cyclotron resonance heating modulation on edge turbulence driving and spreading in HL-2A tokamak

CSTR: 32037.14.aps.74.20241263
PDF
HTML
导出引用
  • 湍流非线性作用产生的等离子体流可以通过剪切抑制湍流及其驱动的输运, 从而改善等离子体约束. 湍流可以由局域梯度驱动及远大于其相关长度的径向位置的湍流传播. 采用快速往复朗缪尔探针阵列在中国环流器2号A(HL-2A)托卡马克上观测了电子回旋共振加热 (electron cyclotron resonance heating, ECRH)调制对边缘湍流驱动和传播的影响. 边缘径向电场、湍流和雷诺协强在ECRH期间均增强且伴随着离子-离子碰撞率降低. 分析表明边缘极向流的增强是由于湍流非线性驱动增大和阻尼减弱的共同作用结果. 进一步分析发现ECRH开启后湍流驱动和传播率均增大, 且湍流驱动率大于湍流传播率, 并与湍流强度做比较. 结果表明ECRH期间边缘湍流驱动和传播共同作用导致湍流强度增加, 进而引起湍流雷诺协强增强并驱动更强的边缘等离子体流. 这些结果阐明了ECRH调制期间边缘湍流驱动和传播对边缘等离子体流和湍流的重要影响.

     

    The plasma flow generated by turbulent nonlinear interaction can improve plasma confinement by suppressing turbulence and its driven transport. Turbulence can be driven by local gradients and propagate radially from far beyond its relevant length. Effects of electron cyclotron resonance heating (ECRH) modulation on edge turbulence driving and spreading are observed for the first time in the edge plasma of the HL-2A tokamak. These experiments are performed by a fast reciprocating Langmuir probe array. When ECRH modulation is applied, both the edge temperature and the edge plasma density are higher, and the radial electric field is stronger. The edge radial electric field, turbulence, and Reynolds stresses are all enhanced when the ECRH is applied, while the ion-ion collision rate is reduced. Figures (a)-(g) show the conditional averages of the ECRH power, turbulence intensity, turbulent Reynolds stress gradient, \boldsymbolE_r\times \boldsymbolB poloidal velocity, density gradient, turbulence drive rate and turbulence spreading rate, respectively. With ECRH applied, both the turbulence intensity and the Reynolds stress gradients increase. The maximum turbulence intensity appears at the beginning of the ECRH switch-off while the maximum stress gradient occurs at the end of the ECRH. The evolution of the \boldsymbolE_r\times \boldsymbolB poloidal velocity is very similar to that of the Reynolds stress gradient. This observation suggests that the poloidal flow is the result of the combined effect of turbulence nonlinear driving and damping. The enhancement of Reynolds stress during ECRH modulation mainly depends on the increase of the turbulence intensity, with the increase in radial velocity fluctuation intensity being more significant. The turbulence drive and spreading rates also increase with ECRH. The maximum drive rate appears at the beginning of the ECRH switch-off, while the maximum spreading rate occurs at the end of the ECRH. This analysis indicates that turbulence driving and spreading are enhanced, with the former being dominant. This result suggests that the enhancements of turbulence driving and spreading lead the turbulence and Reynolds stress to increase, and thus producing the stronger edge flows.

     

    目录

    /

    返回文章
    返回