Zhang Hui, Zong Qiugang, Connor Hyunju, Delamere Peter, Facskó Gábor, Han Desheng, Hasegawa Hiroshi, Kallio Esa, Kis Árpád, Le Guan, Lembège Bertrand, Lin Yu, Liu Terry, Oksavik Kjellmar, Omidi Nojan, Otto Antonius, Ren Jie, Shi Quanqi, Sibeck David, Yao Shutao
Physics Department & Geophysical Institute, University of Alaska Fairbanks, 2156 Koyukuk Drive, Fairbanks, AK 99775 USA.
Shandong University, Weihai, China.
Space Sci Rev. 2022;218(5):40. doi: 10.1007/s11214-021-00865-0. Epub 2022 Jun 28.
Dayside transients, such as hot flow anomalies, foreshock bubbles, magnetosheath jets, flux transfer events, and surface waves, are frequently observed upstream from the bow shock, in the magnetosheath, and at the magnetopause. They play a significant role in the solar wind-magnetosphere-ionosphere coupling. Foreshock transient phenomena, associated with variations in the solar wind dynamic pressure, deform the magnetopause, and in turn generates field-aligned currents (FACs) connected to the auroral ionosphere. Solar wind dynamic pressure variations and transient phenomena at the dayside magnetopause drive magnetospheric ultra low frequency (ULF) waves, which can play an important role in the dynamics of Earth's radiation belts. These transient phenomena and their geoeffects have been investigated using coordinated in-situ spacecraft observations, spacecraft-borne imagers, ground-based observations, and numerical simulations. Cluster, THEMIS, Geotail, and MMS multi-mission observations allow us to track the motion and time evolution of transient phenomena at different spatial and temporal scales in detail, whereas ground-based experiments can observe the ionospheric projections of transient magnetopause phenomena such as waves on the magnetopause driven by hot flow anomalies or flux transfer events produced by bursty reconnection across their full longitudinal and latitudinal extent. Magnetohydrodynamics (MHD), hybrid, and particle-in-cell (PIC) simulations are powerful tools to simulate the dayside transient phenomena. This paper provides a comprehensive review of the present understanding of dayside transient phenomena at Earth and other planets, their geoeffects, and outstanding questions.
向日侧瞬变现象，如热流异常、前震气泡、磁鞘喷流、通量传输事件和表面波，经常在弓形激波上游、磁鞘内以及磁层顶被观测到。它们在太阳风 - 磁层 - 电离层耦合中起着重要作用。与太阳风动压变化相关的前震瞬变现象会使磁层顶变形，进而产生与极光电离层相连的场向电流（FACs）。向日侧磁层顶的太阳风动压变化和瞬变现象会驱动磁层超低频（ULF）波，这在地球辐射带的动力学中可能起重要作用。这些瞬变现象及其地球效应已通过协调的原位航天器观测、航天器搭载成像仪、地面观测和数值模拟进行了研究。“星簇”（Cluster）、“THEMIS”、“地球尾”（Geotail）和“磁层多尺度”（MMS）等多任务观测使我们能够详细追踪不同空间和时间尺度上瞬变现象的运动和时间演化，而地面实验可以观测瞬变磁层顶现象的电离层投影，例如由热流异常驱动的磁层顶波或由突发重联产生的通量传输事件在其整个经度和纬度范围内的情况。磁流体动力学（MHD）、混合和粒子模拟（PIC）是模拟向日侧瞬变现象的有力工具。本文全面综述了目前对地球和其他行星向日侧瞬变现象、它们的地球效应以及未解决问题的理解。
