Spectral characteristics of geodesic acoustic mode in the HL-2A tokamak
Spectral characteristics of geodesic acoustic mode in the HL-2A tokamak
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HL-2A托卡马克测地线声模的频谱特性
DOI：
10.1088/0741-3335/50/4/045002
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发表时间：
2008-02
影响因子：
2.2
通讯作者：
中科院分区：
文献类型：
--
作者：
将两点相关技术和双谱分析应用于环六七二号A（HL-2A）托卡马克静电探针阵列测量的电场波动，系统地研究了测地声模（GAM）的谱特性。首次测量了GAM的三维波数和频谱。频谱为 GAM 提供了明确的证据，其特征为 kθ = kphi = 0 和 krρi ≈ 0.04–0.09，半峰全宽 Δkrρi ≈ 0.03–0.07。径向波数谱显示局域 GAM 包以大致相同的相位和群速度向外传播。涉及雷诺应力的交叉双相干性和电势 ( )、径向电场 ( ) 和密度 ( ) 波动的自双相干性已被估计以进行比较。除了密度涨落的自双相干求和之外，在所有求和双相干中都观察到了 GAM 和宽带湍流之间的强非线性耦合。对于满足 f1 + f2 = fGAM 的相互作用，所有交叉和自双相干性（密度波动的自双相干性除外）被发现在频率范围 f1 < 100 kHz 内具有峰值特征。该峰值特征可能反映了 GAM 与环境湍流之间非线性耦合的共振特性。
The spectral characteristics of the geodesic acoustic mode (GAM) are investigated systematically by applying the two-point correlation technique and bispectral analysis to electric field fluctuations measured by electrostatic probe arrays on the HuanLiuqi-2A (HL-2A) tokamak. The three-dimensional wavenumber and frequency spectrum for the GAM has been measured for the first time. The spectrum provides definite evidence for the GAM which is characterized by kθ = kϕ = 0 and krρi ≈ 0.04–0.09 with the full width at half maximum Δkrρi ≈ 0.03–0.07. The radial wavenumber spectrum shows that the localized GAM packet propagates in the outward direction with approximately the same phase and group velocity. The cross-bicoherences involving the Reynolds stress and auto-bicoherences of potential ( ), radial electric field ( ) and density ( ) fluctuations have been estimated for comparisons. Strong nonlinear coupling between the GAM and broadband turbulence is observed in all summed bicoherences, except for the summed auto-bicoherence of density fluctuations. All cross- and auto-bicoherences, except for the auto-bicoherence of density fluctuations, for interactions satisfying f1 + f2 = fGAM are found to have a peaked feature in the frequency range f1 < 100 kHz. This peaked feature might reflect the resonance property in the nonlinear coupling between the GAM and ambient turbulence.
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影响因子：
2.2
作者：
R. Waltz;G. Kerbel;J. Milovich
通讯作者：
R. Waltz;G. Kerbel;J. Milovich
影响因子：
8.6
作者：
R. Moyer;G. Tynan;Christopher Holland;M. Burin
通讯作者：
R. Moyer;G. Tynan;Christopher Holland;M. Burin
影响因子：
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通讯作者：
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影响因子：
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作者：
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影响因子：
2.2
作者：
T S Hahm;K. Burrell;Z. Lin;R. Nazikian;E. Synakowski
通讯作者：
T S Hahm;K. Burrell;Z. Lin;R. Nazikian;E. Synakowski