标题： 近日太阳风湍流中各向异性与静止背景场的标度关系 显示英文标题

标题： Scaling anisotropy with stationary background field in the near-Sun solar wind turbulence

摘要： 磁波动的标度为理解太阳风湍流提供了关键信息。 然而，观测到的磁波动不仅包含湍流，还包含磁结构，导致时间平稳性的破坏。 这种破坏会掩盖真实的标度，并影响相对于局部背景磁场采样角度的确定。 在此，为了研究标度各向异性，我们利用一个简单但有效的准则$\phi<10^\circ$来确保磁场的时间平稳性，其中$\phi$是将区间分成两半后两个平均磁场之间的夹角。 我们首次基于帕克太阳探测器（PSP）在 0.17 天文单位处的测量数据，对近日太阳风湍流在平稳条件下的结构函数高阶统计量进行研究，以探讨标度各向异性。 我们发现磁场所得的标度指数$\xi$与阶数$p$呈线性关系，接近$\xi(p)=p/4$。 当使用平稳背景磁场进行测量时，磁迹结构函数的多分形标度在局部磁场垂直于采样方向时接近$\xi(p)=p/3$，在局部磁场平行于采样方向时接近$\xi(p)=p/4$。 速度迹结构函数的标度具有类似但不那么显著的变化。 近日太阳风湍流与近地太阳风湍流表现出不同的标度各向异性，这表明太阳风膨胀过程中非线性相互作用过程的演化。 显示英文摘要

摘要： The scaling of magnetic fluctuations provides crucial information for the understanding of solar wind turbulence. However, the observed magnetic fluctuations contain not only turbulence but also magnetic structures, leading to the violation of the time stationarity. This violation would conceal the true scaling and influence the determination of the sampling angle with respect to the local background magnetic field. Here, to investigate the scaling anisotropy, we utilize an easy but effective criterion $\phi<10^\circ$ to ensure the time stationarity of the magnetic field, where $\phi$ is the angle between the two averaged magnetic fields after cutting the interval into two halves. We study the scaling anisotropy using higher-order statistics of structure functions under the condition of stationarity for the near-Sun solar wind turbulence for the first time based on measurements obtained from Parker Solar Probe (PSP) at 0.17 au. We find that the scaling indices $\xi$ of magnetic field show a linear dependence on the order $p$ close to $\xi(p)=p/4$. The multifractal scaling of magnetic-trace structure functions becomes monoscaling close to $\xi(p)=p/3$ with the local magnetic field perpendicular to the sampling direction and close to $\xi(p)=p/4$ with the local magnetic field parallel to the sampling direction when measured with the stationary background magnetic field. The scaling of velocity-trace structure functions has similar but less significant changes. The near-Sun solar wind turbulence displays different scaling anisotropies with the near-Earth solar wind turbulence, suggesting the evolution of the nonlinear interaction process during the solar wind expansion.