Synergistic effects between two frequencies of lower hybrid (LH) waves—operating at 2.45 and 4.6 GHz—were observed in experiment on EAST for the first time. At low density ($n_{e,\mathit{lin}}\approx 2.0\times 10^{19}\hspace{0.17em}{\mathrm{m}}^{-3}$), simultaneous injection of a 65/35 mix of 2.45/4.6 GHz power achieved an lower hybrid current drive efficiency that was 25% higher than what should be expected from the linear combination of the two sources. The experiment was interpreted with time-dependent simulations, using the equilibrium and transport solver TRANSP, coupled with the ray-tracing code GENRAY and the Fokker–Planck solver CQL3D. For each discharge, profiles of current and hard x-rays from simulation and measurement agree within uncertainties. An examination of the electron distribution function indicates that the LH synergy is supported by the increased width of the LH resonance plateau in the simultaneous injection case compared to independent injection.

中文翻译：

---

观察 EAST 中两个频率下低混合波之间的协同作用

在 EAST 上的实验中首次观察到两种低混合 (LH) 波频率（在 2.45 和 4.6 GHz 下运行）之间的协同效应。在低密度 ($n_{\mathrm{电子},\mathit{林}}\approx 2.0\times 10^{19}\hspace{0.17em}{\mathrm{米}}^{-3}$)，同时注入 65/35 混合 2.45/4.6 GHz 功率实现了较低的混合电流驱动效率，比两个源的线性组合预期的效率高 25%。使用平衡和传输求解器TRANSP以及光线追踪代码GENRAY和 Fokker-Planck 求解器CQL3D，通过与时间相关的模拟来解释实验。对于每次放电，来自模拟和测量的电流和硬 X 射线的分布在不确定性范围内一致。对电子分布函数的检查表明，与独立注入相比，同时注入情况下 LH 共振平台的宽度增加支持 LH 协同作用。