• ISSN 2097-1893
  • CN 10-1855/P
吕景天,张效信,何飞,黄聪. 2023. 地球等离子体层研究进展. 地球与行星物理论评(中英文),54(4):417-433. doi: 10.19975/j.dqyxx.2022-064
引用本文: 吕景天,张效信,何飞,黄聪. 2023. 地球等离子体层研究进展. 地球与行星物理论评(中英文),54(4):417-433. doi: 10.19975/j.dqyxx.2022-064
Lü J T, Zhang X X, He F, Huang C. 2023. State studies of Earth's plasmasphere. Reviews of Geophysics and Planetary Physics, 54(4): 417-433 (in Chinese). doi: 10.19975/j.dqyxx.2022-064
Citation: Lü J T, Zhang X X, He F, Huang C. 2023. State studies of Earth's plasmasphere. Reviews of Geophysics and Planetary Physics, 54(4): 417-433 (in Chinese). doi: 10.19975/j.dqyxx.2022-064

地球等离子体层研究进展

State studies of Earth's plasmasphere

  • 摘要: 地球等离子体层作为内磁层的重要组成部分,在空间天气过程的发生和发展过程中都起着非常重要的作用. 地球等离子体层是由上行电离层粒子被地球磁力线捕获而形成的圆环状冷的等离子体区域. 等离子体层的外边界称为等离子体层顶,在该区域的等离子体层密度在0.5个地球半径内下降了1~2个数量级. 地球等离子体层结构的动态变化特征是空间环境扰动状态的指示器,其结构形态和动力学过程受地磁场和电场控制,而地磁场短期变化源于太阳活动引起的日地扰动. 地磁暴期间等离子体层的大规模结构演化影响等离子体层中波的产生和传播,从而影响波-粒子相互作用,导致内磁层中电子和离子的空间分布发生变化,进而影响其它磁层和电离层过程. 对地球等离子体层进行进一步研究,对揭示太阳风-磁层-电离层耦合过程中的质量输运和能量转移、空间天气预报等方面都具有重要的意义. 本文对等离子体层和地磁活动的关系、等离子体层中的波、顶部电离层及等离子体层电子含量的变化规律和等离子体层模型等方面的研究进展进行了介绍. 最后,我们还对等离子体层研究方面一些亟待解决的问题进行了展望.

     

    Abstract: As an important part of the inner magnetosphere, the Earth's plasmasphere plays a vital role in linking the occurrence and development of space weather processes. The Earth's plasmasphere is a torus-shaped cold (< 10 eV) and dense (10~104 cm−3) plasma region of ionospheric origin co-rotating with the planet. The plasmasphere contains several populations of particles such as electrons, H+, He+, and O+ ions. The outer boundary of the plasmasphere is defined by a sharp gradient of density called the plasmapause, in which the density decreases by 1~ 2 orders of magnitude within 0.5 RE (the Earth radius). Additionally, large scale plasmaspheric features have been observed, including shoulders, plumes, notches, bulges, and refiling. The Earth's plasmasphere is dynamic, and the abundance of particles in it changes substantially with interplanetary and geomagnetic activity. The large-scale structure evolution of the plasmasphere during geomagnetic storms controls the generation and propagation of waves in the plasmasphere, thus affecting the wave-particles interaction, resulting in a change in the spatial distribution of electrons and ions in the plasmasphere, and then affecting other magnetospheric and ionospheric processes. During periods of geomagnetic storms, the plasmaspheric material eroded is transported sunward and observed near the dayside magnetopause regularly. This local plasmaspheric density enhancement greatly impacts global large-scale convection. Therefore, the plasmaspheric density is undoubtedly an important parameter in space weather. The structural dynamic change of the Earth's plasmasphere is an indicator of the disturbance state of the space weather environment. Its structural form and dynamic process are controlled by the geomagnetic activity, and the short-term changes in the geomagnetic field originate from the sun-terrestrial disturbance caused by solar activity. The high-speed plasma ejected from the solar corona impacts the Earth and induces large-scale convective motion in the magnetosphere. Part of the energy enters the magnetosphere, causing disturbances in its inner regions, including the plasmasphere. Further research on the Earth’s plasmasphere is of great significance to reveal the mass transport and energy transfer in the solar wind-magnetosphere-ionosphere coupling process, and space weather forecast. Here, we introduce the research progress in the response of the plasmasphere to geomagnetic activities, the waves in the plasmasphere, variation of the electron content in the topside ionosphere and plasmasphere, and plasmasphere models. Finally, we also list some important issues for future studies.

     

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