Kinetic simulations of magnetized turbulence in astrophysical plasmas.
Kinetic simulations of magnetized turbulence in astrophysical plasmas.
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DOI：
10.1103/physrevlett.100.065004
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发表时间：
2007-11
影响因子：
8.6
通讯作者：
G. Howes;W. Dorland;S. Cowley;S. Cowley;G. Hammett;E. Quataert;A. Schekochihin;T. Tatsuno
中科院分区：
文献类型：
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作者：
G. Howes;W. Dorland;S. Cowley;S. Cowley;G. Hammett;E. Quataert;A. Schekochihin;T. Tatsuno
本文首次在离子拉莫尔半径（离子陀螺尺度）尺度上对均匀弱碰撞等离子体中的磁化湍流进行了从头算、全电磁动力学模拟。磁场能谱和电场能谱在离子陀螺尺度处出现断裂；光谱斜率与离子回旋标度以上的alfv<s:1>波浪的临界平衡湍流（光谱指数为-5/3）和离子回旋标度以下的动力学alfv<s:1>波浪（磁波动的光谱指数为-7/3，电波动的光谱指数为-1/3）的标度预测相一致。这种行为在质量上也与太阳风湍流的现场测量一致。我们的发现支持了太阳风湍流波动的频率远低于离子回旋频率的假设，无论是在离子回旋尺度之上还是之下。
This Letter presents the first ab initio, fully electromagnetic, kinetic simulations of magnetized turbulence in a homogeneous, weakly collisional plasma at the scale of the ion Larmor radius (ion gyroscale). Magnetic- and electric-field energy spectra show a break at the ion gyroscale; the spectral slopes are consistent with scaling predictions for critically balanced turbulence of Alfvén waves above the ion gyroscale (spectral index -5/3) and of kinetic Alfvén waves below the ion gyroscale (spectral indices of -7/3 for magnetic and -1/3 for electric fluctuations). This behavior is also qualitatively consistent with in situ measurements of turbulence in the solar wind. Our findings support the hypothesis that the frequencies of turbulent fluctuations in the solar wind remain well below the ion cyclotron frequency both above and below the ion gyroscale.