论文标题
同时测量喷气机中不稳定和稳定的Alfvén本特征模
Simultaneous measurements of unstable and stable Alfvén Eigenmodes in JET
论文作者
论文摘要
在本文中，我们报告了对不稳定和稳定的环形性诱导的Alfvén本征（TAE）的新型实验观察结果，该特征模（TAES）同时在喷射Tokamak等离子体中测量。使用三离子加热方案（D-DNBI-3HE）用于加速杜特龙，从而使taes稳固，从而破坏了to toidal模式数n = 3-5，每种taes在模式幅度下都降低。同时，Alfvéneigenmode主动诊断会引起稳定的n = 6 TAE激发，总归一化阻尼率$-γ/ω_0\约$ 1％-4％。使用代码Nova-K和Mega的混合动力学MHD建模都可以找到与实验相似的频率，模式结构和径向位置的特征模型。 Nova-K与N = 3、4和6 TAE表现出良好的一致性，与不确定性内N = 6模式的阻尼率匹配，并将辐射阻尼识别为主要贡献。在所有模式下都发现了与大型的一致性：不稳定的n = 3-5和稳定的n = 2，6模式，后两个人分别通过较高的内在阻尼和较低的快速离子驱动稳定。尽管一些差异仍然有待解决，但这种独特的验证工作使我们对未来融合设备的TAE稳定性预测有信心。
In this paper, we report the novel experimental observation of both unstable and stable Toroidicity-induced Alfvén Eigenmodes (TAEs) measured simultaneously in a JET tokamak plasma. The three-ion-heating scheme (D-DNBI-3He) is employed to accelerate deuterons to MeV energies, thereby destabilizing TAEs with toroidal mode numbers n = 3-5, each decreasing in mode amplitude. At the same time, the Alfvén Eigenmode Active Diagnostic resonantly excites a stable n = 6 TAE with total normalized damping rate $-γ/ω_0 \approx$ 1%-4%. Hybrid kinetic-MHD modeling with codes NOVA-K and MEGA both find eigenmodes with similar frequencies, mode structures, and radial locations as in experiment. NOVA-K demonstrates good agreement with the n = 3, 4, and 6 TAEs, matching the damping rate of the n = 6 mode within uncertainties and identifying radiative damping as the dominant contribution. Improved agreement is found with MEGA for all modes: the unstable n = 3-5 and stable n = 2, 6 modes, with the latter two stabilized by higher intrinsic damping and lower fast ion drive, respectively. While some discrepancies remain to be resolved, this unique validation effort gives us confidence in TAE stability predictions for future fusion devices.
