Scaling Anisotropy with Stationary Background Field in Near-Sun Solar Wind Turbulence

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