论文标题
帕克太阳能探针揭示了磁场光谱在太阳风湍流的动力尺度上的各向异性
Anisotropy of Magnetic Field Spectra at Kinetic Scales of Solar Wind Turbulence as Revealed by Parker Solar Probe in the Inner Heliosphere
论文作者
论文摘要
使用在内部地层内获取的Parker太阳能探针数据，我们研究了在动力学尺度（即围绕亚离子尺度）在内层中磁场光谱的功率和空间各向异性。我们发现，磁光谱的强各向异性发生在动力尺度上，在垂直方向上相对于局部磁场（形成一个具有平均流速的角度Theta_b）。当theta_b的角度从90变为180（OR 0）时，磁光谱的光谱指数从-3.2到-5.8，表明光谱指数的强各向异性发生在太阳风湍流中的动力学尺度上。使用基于磁性螺旋性的诊断，我们表明光谱指数的各向异性可以通过在动力学尺度下携带级联反应的等离子体模式的性质来解释。我们根据现有的理论和当前的发展讨论我们的发现。
Using the Parker Solar Probe data taken in the inner heliosphere, we investigate the power and spatial anisotropy of magnetic-field spectra at kinetic scales (i.e., around sub-ion scales) in solar wind turbulence in the inner heliosphere. We find that strong anisotropy of magnetic spectra occurs at kinetic scales with the strongest power in the perpendicular direction with respect to the local magnetic field (forming an angle theta_B with the mean flow velocity). The spectral index of magnetic spectra varies from -3.2 to -5.8 when the angle theta_B changes from 90 to 180 (or 0) deg, indicating that strong anisotropy of the spectral indices occurs at kinetic scales in the solar wind turbulence. Using a diagnosis based on the magnetic helicity, we show that the anisotropy of the spectral indices can be explained by the nature of the plasma modes that carry the cascade at kinetic scales. We discuss our findings in light of existing theories and current development in the field.
