The geodesic acoustic mode (GAM) is a high-frequency (HF) branch of zonal flows, considered as a mechanism of the turbulence self-regulation, which affects the radial transport of energy and particles. The GAM studies were performed in the T-10 tokamak, using the heavy ion beam probing (HIBP). The power spectral density of plasma potential has the main GAM peak with frequency fGAM ∼ 20 kHz, and two satellite peaks, HF and low-frequency (LF) ones. In ohmic plasmas and in discharges with moderate electron cyclotron resonance heating (ECRH), both satellites are separated from the main peak by the Δf ∼ ± 3−4 kHz. Each of three peaks has the character of a global eigenmode of plasma oscillations with the frequency and amplitude of fluctuations almost constant in a wide radial region from the core to the edge. At the edge, the amplitude of the GAM peaks decreases to zero. Thus, the radial dependence of the GAM frequency does not obey the local Winsor formula fGAM(r) ∼ Cs(r)/R, where is the ion-sound velocity. Nevertheless, in ohmic discharges and at the moderate ECRH power PEC < 0.5 MW, the frequencies of all peaks depend on Cs, taken in their birth points located at the edge. With a further increase in temperature or at the powerful ECRH (0.5 MW < PEC < 2.2 MW) the frequencies of all peaks deviate from the Cs dependence and saturate. When the temperature increases, the frequency difference between the main GAM peak and the HF-satellite decreases, and these two peaks merge into the single one, reaching the upper limit for fGAM. The bicoherence analysis finds the three-wave coupling of GAM with quasicoherent and stochastic LF turbulent modes. Each peak has its own frequency range of coupling.
地磁声模（GAM）是带状流的高频（HF）分支，被视为湍流自调节的一种机制，影响能量和粒子的径向输运。在T-10托卡马克中，利用重离子束探针（HIBP）进行了GAM研究。等离子体电势的功率谱密度具有主GAM峰，频率为fGAM ∼ 20 kHz，以及两个卫星峰，即高频（HF）和低频（LF）峰。在欧姆等离子体和具有中等电子回旋共振加热（ECRH）的放电中，两个卫星峰与主峰之间的间隔为Δf ∼ ± 3−4 kHz。三个峰中的每一个都具有等离子体振荡全局本征模的特征，其频率和涨落幅度在从芯部到边缘的宽径向区域内几乎恒定。在边缘处，GAM峰的幅度降至零。因此，GAM频率的径向依赖性不遵循局域Winsor公式fGAM(r) ∼ Cs(r)/R，其中为离子声速。然而，在欧姆放电和中等ECRH功率PEC < 0.5 MW条件下，所有峰的频率依赖于Cs，该Cs取自位于边缘的其产生点。随着温度的进一步升高或在强ECRH（0.5 MW < PEC < 2.2 MW）条件下，所有峰的频率偏离Cs依赖性并趋于饱和。当温度升高时，主GAM峰与HF卫星峰之间的频率差减小，这两个峰合并为单一峰，达到fGAM的上限。双相干性分析发现了GAM与准相干和随机LF湍流模之间的三波耦合。每个峰具有其各自的耦合频率范围。