Formation of thin current sheets in Earth's magnetotail is a critical element of the magnetosphere dynamics. The configuration and stability of these thin current sheets control the onset of magnetic reconnection and particle acceleration in the magnetotail during substorms and other geomagnetic activities. In recent years, multipoint observations, kinetic and hybrid simulations have significantly improved our understanding of the structure and dynamics of thin current sheets, including their ion kinetic physics. Global hybrid simulations have also revealed many details of ion kinetics in thin current sheet physics. In this paper we review current understanding of current sheet physics and discuss our recent observational and simulation results on thin current sheet formation, emphasizing the kinetics of current sheet thinning, multi-component ion populations, the role of electron anisotropy and ion agyrotropy, and the role of the ionosphere.

在地球磁尾中形成薄电流片是磁层动力学的一个关键因素。这些薄电流片的配置和稳定性控制着亚暴和其他地磁活动期间磁尾中磁重联和粒子加速的开始。近年来，多点观测、动力学和混合模拟显着提高了我们对薄电流片结构和动力学的理解，包括它们的离子动力学物理。全局混合模拟还揭示了薄电流片物理中离子动力学的许多细节。在本文中，我们回顾了当前对电流片物理的理解，并讨论了我们最近对薄电流片形成的观察和模拟结果，强调了电流片变薄的动力学，