High-order plasma shaping (mainly elongation and shift, as opposed to low-order toroidicity) is shown, under certain conditions, to open gaps in the coupled shear-Alfvn and acoustic continua at frequencies significantly above the values predicted by previous theories. Global eigenmodes in these gaps, which lie between the frequencies of geodesic acoustic modes and toroidicity-induced Alfvn eigenmodes, are found unstable to hot-ion populations typical of tokamak operation, whilst their fundamental resonances with circulating particles are shown to take place at velocities near the geometric mean of the Alfvn and sound speeds. Therefore, such eigenmodes are expected to be observed near the predicted frequencies at operating tokamaks, playing a still unexplored role in magnetohydrodynamic spectroscopy as well as in the stability of next-step fusion experiments.

在某些条件下，高阶等离子体成形（主要是伸长和位移，而不是低阶环面）显示出在耦合剪切-Alfvn 和声学连续体中以明显高于先前理论预测值的频率打开间隙。这些间隙中的全局本征模位于测地线声模频率和环面性引起的 Alfvn 本征模频率之间，对典型的托卡马克操作的热离子群不稳定，而它们与循环粒子的基本共振显示发生在接近Alfvn 和声速的几何平均值。因此，预计在运行托卡马克的预测频率附近会观察到这种本征模式，