Interplanetary coronal mass ejections (ICMEs) are large-scale heliospheric transients that originate from the Sun. When an ICME is sufficiently faster than the preceding solar wind, a shock wave develops ahead of the ICME. The turbulent region between the shock and the ICME is called the sheath region. ICMEs and their sheaths and shocks are all interesting structures from the fundamental plasma physics viewpoint. They are also key drivers of space weather disturbances in the heliosphere and planetary environments. ICME-driven shock waves can accelerate charged particles to high energies. Sheaths and ICMEs drive practically all intense geospace storms at the Earth, and they can also affect dramatically the planetary radiation environments and atmospheres. This review focuses on the current understanding of observational signatures and properties of ICMEs and the associated sheath regions based on five decades of studies. In addition, we discuss modelling of ICMEs and many fundamental outstanding questions on their origin, evolution and effects, largely due to the limitations of single spacecraft observations of these macro-scale structures. We also present current understanding of space weather consequences of these large-scale solar wind structures, including effects at the other Solar System planets and exoplanets. We specially emphasize the different origin, properties and consequences of the sheaths and ICMEs.

行星际日冕物质抛射（ICME）是源自太阳的大规模日光层瞬变。当 ICME 比之前的太阳风快得多时，冲击波就会在 ICME 之前产生。激波和 ICME 之间的湍流区域称为鞘层区域。从基本等离子体物理学的角度来看，ICME 及其鞘层和激波都是有趣的结构。它们也是日光层和行星环境中空间天气扰动的关键驱动因素。 ICME 驱动的冲击波可以将带电粒子加速到高能量。鞘层和 ICME 驱动了地球上几乎所有强烈的地球空间风暴，它们还可以极大地影响行星辐射环境和大气。本综述重点关注基于五十年研究的当前对 ICME 和相关鞘区域的观测特征和特性的理解。此外，我们还讨论了 ICME 的建模以及关于其起源、演化和影响的许多基本的悬而未决的问题，这在很大程度上是由于单个航天器对这些宏观尺度结构的观测的局限性。我们还介绍了目前对这些大型太阳风结构的空间天气后果的理解，包括对其他太阳系行星和系外行星的影响。我们特别强调护套和 ICME 的不同来源、特性和后果。