论文标题
在近地和近阳光的太阳风中观察到的空间等离子体中的动力学湍流
Kinetic turbulence in space plasmas observed in the near-Earth and near-Sun solar wind
论文作者
论文摘要
当强迫的尺度比耗散的尺度大得多时，湍流会在任何应力流中发展。在中性流体中，它由物理空间中的混乱运动组成，但在傅立叶空间中具有通用能量谱。间歇性（非高斯波动统计）是另一个一般特性，它与一致结构的存在有关。空间等离子体也是动荡的。在这里，我们专注于动力学等离子体量表，这些等离子量表尚未得到很好的理解。我们解决以下基本问题：（1）动力学尺度上的湍流是否形成了通用频谱？ （2）波动的本质是什么？使用太阳风中的测量值我们表明，来自太阳的0.3、0.6和0.9 au的动力湍流的磁光谱的形状与接近地球轨道的1 au处的形状相同，表明现象的普遍性。形成这种频谱的波动通常是非线性相互作用的涡流，往往会产生磁丝。
Turbulence develops in any stressed flow when the scales of the forcing are much larger than those of the dissipation. In neutral fluids, it consists of chaotic motions in physical space but with a universal energy spectrum in Fourier space. Intermittency (non-Gaussian statistics of fluctuations) is another general property and it is related to the presence of coherent structures. Space plasmas are turbulent as well. Here, we focus on the kinetic plasma scales, which are not yet well understood. We address the following fundamental questions: (1) Do the turbulent fluctuations at kinetic scales form a universal spectrum? and (2) What is the nature of the fluctuations? Using measurements in the solar wind we show that the magnetic spectra of kinetic turbulence at 0.3, 0.6 and 0.9 AU from the Sun have the same shape as the ones close to the Earth orbit at 1 AU, indicating universality of the phenomenon. The fluctuations, which form this spectrum, are typically non-linearly interacting eddies that tend to generate magnetic filaments.
