Heat pulse propagation and anomalous electron heat transport measurements on the optimized stellarator W7-X
Heat pulse propagation and anomalous electron heat transport measurements on the optimized stellarator W7-X
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DOI：
10.1088/1741-4326/abea55
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发表时间：
2021-05
期刊：
影响因子：
3.3
通讯作者：
G. Weir;P. Xanthopoulos;M. Hirsch;U. Höfel;T. Stange;N. Pablant;O. Grulke;S. Äkäslompolo;J. Alcuson;S. Bozhenkov;M. Beurskens;A. Dinklage;G. Fuchert;J. Geiger;Matt Landreman;A. Langenberg;S. Lazerson;N. Marushchenko;E. Pasch;J. Schilling;E. Scott;Y. Turkin;T. Klinger
中科院分区：
文献类型：
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作者：
G. Weir;P. Xanthopoulos;M. Hirsch;U. Höfel;T. Stange;N. Pablant;O. Grulke;S. Äkäslompolo;J. Alcuson;S. Bozhenkov;M. Beurskens;A. Dinklage;G. Fuchert;J. Geiger;Matt Landreman;A. Langenberg;S. Lazerson;N. Marushchenko;E. Pasch;J. Schilling;E. Scott;Y. Turkin;T. Klinger
优化的仿星器温德尔斯坦7-X（W7-X）被设计成具有近似准等动力学的磁位形，与经典仿星器相比具有减少的新古典输运，并且湍流输运被预期为穿过等离子体小半径的异常热输运的重要来源。离子温度梯度驱动模和俘获电子模（TEM）被认为是体积平均压强低于1%的W7-X等离子体中离子尺度湍流的主要原因。在这项工作中，电子温度梯度驱动的湍流被证明是一个很好的候选人所观察到的电子热通量的解释，在内部等离子体区域的密度梯度是弱的（在外部区域，一个相对较强的密度梯度将驱动额外的TEM湍流）。电子回旋共振加热功率和等离子体密度扫描过程中测量的实验电子热传输进行比较，新古典预测，并在瞬态传输实验过程中测量的电子热传输的刚度是在三个常见的磁配置的W7-X。在低β-ε等离子体放电中，由热脉冲与功率平衡扩散率之比（χeHP/χePB）量化的电子热通量的刚度被测量为小于2，并且随着碰撞性的增加而呈下降趋势。
The optimized stellarator Wendelstein 7-X (W7-X) is designed to have an approximately quasi-isodynamic magnetic configuration with reduced neoclassical transport in comparison to a classical stellarator, and turbulent transport is expected to be a significant source of anomalous heat transport across the plasma minor radius. The ion temperature gradient driven mode and the trapped electron mode (TEM) are thought to be responsible for the ion-scale turbulence in W7-X plasmas with volume averaged pressure below 1%. In this work, the electron temperature gradient driven turbulence is shown to be a good candidate for the explanation of the observed electron heat flux, in the inner plasma region where the density gradient is weak (in the outer region, a relatively stronger density gradient would drive additional TEM turbulence). The experimental electron heat transport measured during electron cyclotron resonant heating power and plasma density scans is compared to neoclassical predictions, and the stiffness in the electron heat transport measured during transient transport experiments is presented in three common magnetic configurations of W7-X. In low-⟨β⟩ plasma discharges, the stiffness in the electron heat flux, quantified by the ratio of the heat pulse to power balance diffusivity, χeHP/χePB , is measured to be less than 2, and trend downwards with increasing collisionality.