The solar wind is a magnetized plasma and as such exhibits collective plasma behavior associated with its characteristic spatial and temporal scales. The characteristic length scales include the size of the heliosphere, the collisional mean free paths of all species, their inertial lengths, their gyration radii, and their Debye lengths. The characteristic timescales include the expansion time, the collision times, and the periods associated with gyration, waves, and oscillations. We review the past and present research into the multi-scale nature of the solar wind based on in-situ spacecraft measurements and plasma theory. We emphasize that couplings of processes across scales are important for the global dynamics and thermodynamics of the solar wind. We describe methods to measure in-situ properties of particles and fields. We then discuss the role of expansion effects, non-equilibrium distribution functions, collisions, waves, turbulence, and kinetic microinstabilities for the multi-scale plasma evolution.

中文翻译：

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太阳风的多尺度性质。

太阳风是一种磁化的等离子体，因此具有与其特征性的时空尺度相关的集体等离子体行为。特征长度尺度包括日光层的大小，所有物种的碰撞平均自由程，惯性长度，回转半径和德拜长度。特征时标包括扩展时间，碰撞时间以及与回转，波动和振荡相关的时间段。我们回顾了基于原位航天器测量和等离子理论的太阳风多尺度性质的过去和现在的研究。我们强调，跨尺度的过程耦合对于太阳风的整体动力学和热力学很重要。我们描述了测量粒子和场的原位特性的方法。