TESTING THE EFFECTS OF EXPANSION ON SOLAR WIND TURBULENCE
TESTING THE EFFECTS OF EXPANSION ON SOLAR WIND TURBULENCE
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DOI：
10.3847/2041-8205/832/1/l16
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发表时间：
2016-11
期刊：
影响因子：
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通讯作者：
D. Vech;C. Chen
中科院分区：
文献类型：
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作者：
D. Vech;C. Chen
我们提出了一个多航天器的方法来测试最近的研究预测太阳风膨胀的径向光谱，方差和本地的三维各向异性的湍流的影响。我们发现，在小尺度（5000- 10，000 km）上，B迹结构函数的功率水平不依赖于相对于径向的采样方向，这表明在这个尺度上，膨胀的影响很小，可能是由于快速的湍流时间尺度。在更大的尺度（110-135 RE）上，径向磁场分量的波动与横向（垂直于径向）磁场分量相比减少了20%，这可能是由于膨胀将波动限制在垂直于径向的平面内。对于局部三维谱各向异性，B迹结构函数表现出相对于径向的采样方向的依赖性。当增量相对于径向垂直时，垂直平面中的各向异性减小，这可能是膨胀的影响。
We present a multi-spacecraft approach to test the predictions of recent studies on the effect of solar wind expansion on the radial spectral, variance, and local 3D anisotropies of the turbulence. We found that on small scales (5000–10,000 km) the power levels of the B-trace structure functions do not depend on the sampling direction with respect to the radial suggesting that on this scale the effect of expansion is small possibly due to fast turbulent timescales. On larger scales (110–135 RE), the fluctuations of the radial magnetic field component are reduced by ∼20% compared to the transverse (perpendicular to radial) ones, which could be due to expansion confining the fluctuations into the plane perpendicular to radial. For the local 3D spectral anisotropy, the B-trace structure functions showed dependence on the sampling direction with respect to radial. The anisotropy in the perpendicular plane is reduced when the increments are taken perpendicular with respect to radial, which could be an effect of expansion.