标题： 太阳风可压缩湍流中反向传播波相互作用的质子加热 显示英文标题

标题： Proton Heating in Solar Wind Compressible Turbulence with Collisions between Counter-propagating Waves

摘要： 磁流体力学湍流被认为在实验室、空间和天体等离子体加热过程中起着至关重要的作用。然而，湍流波动与粒子动力学之间的精确联系尚未建立。在这里，我们基于风号航天器测量的太阳风数据中的波特征和质子速度分布，提供了等离子体湍流加热的明确证据。首次报告了在太阳风湍流中同时观测到反向传播的磁流体力学波。与传统模型中反向传播的阿尔芬波不同，在这种新型的可压缩太阳风湍流中，迎面而来的慢模磁声波（SMW）遇到了背向传播的阿尔芬波（AW）。反向传播的AW和SMW分别对应于不平衡Elsässer变量的主要和次要种群。从一个波可能的振荡方向与另一个波可能的传播方向之间的非正交性推断出AW和SMW之间的非线性相互作用。相关质子的速度分布显示出双向不对称束：迎面而来的束表现为短而窄的模式，而背向传播的束则表现为宽广延伸的尾部。研究表明，多种波粒相互作用，即与AW和SMW在动能尺度上的回旋共振和朗道共振一起，正在发生以共同加热质子的横向和纵向运动。 显示英文摘要

摘要： Magnetohydronamic turbulence is believed to play a crucial role in heating the laboratorial, space, and astrophysical plasmas. However, the precise connection between the turbulent fluctuations and the particle kinetics has not yet been established. Here we present clear evidence of plasma turbulence heating based on diagnosed wave features and proton velocity distributions from solar wind measurements by the Wind spacecraft. For the first time, we can report the simultaneous observation of counter-propagating magnetohydrodynamic waves in the solar wind turbulence. Different from the traditional paradigm with counter-propagating Alfv\'en waves, anti-sunward Alfv\'en waves (AWs) are encountered by sunward slow magnetosonic waves (SMWs) in this new type of solar wind compressible turbulence. The counter-propagating AWs and SWs correspond respectively to the dominant and sub-dominant populations of the imbalanced Els\"asser variables. Nonlinear interactions between the AWs and SMWs are inferred from the non-orthogonality between the possible oscillation direction of one wave and the possible propagation direction of the other. The associated protons are revealed to exhibit bi-directional asymmetric beams in their velocity distributions: sunward beams appearing in short and narrow patterns and anti-sunward broad extended tails. It is suggested that multiple types of wave-particle interactions, i.e., cyclotron and Landau resonances with AWs and SMWs at kinetic scales, are taking place to jointly heat the protons perpendicularly and parallel.