极地研究 ›› 2018, Vol. 30 ›› Issue (3): 235-250.DOI: 10.13679/j.jdyj.20180020

• 研究综述 • 上一篇    下一篇

基于北极黄河站观测的日侧极光研究新进展

韩德胜胡泽骏2  陈相材刘建军胡红桥杨惠根2   

  1. 1. 同济大学地球与海洋学院, 海洋地质国家重点实验室, 上海 200092;
    2. 中国极地研究中心, 上海 200136
  • 收稿日期:2018-04-12 修回日期:2018-05-29 出版日期:2018-09-30 发布日期:2018-09-30
  • 通讯作者: 韩德胜
  • 基金资助:

    国家自然科学基金项目(41431072, 41474146, 41674169, 41774174)、国家海洋局极地考察办公室对外合作项目(201608)、浦东新区科技发展基金(Pkj2013-z01)资助

Recent results obtained from dayside optical auroral observations at Yellow River Station

Han Desheng1, Hu Zejun2, Chen Xiangcai2, Liu Jianjun2, Hu Hongqiao2, Yang Huigen2     

  • Received:2018-04-12 Revised:2018-05-29 Online:2018-09-30 Published:2018-09-30

摘要:

回顾了基于中国黄河站全天空极光观测对日侧弥散极光与喉区极光研究的最新进展。首先, 利用黄河站极光观测, 对日侧弥散极光展开系统性分类与统计研究, 对这一重要空间物理现象取得新认识, 指出日侧弥散极光对研究日侧外磁层冷等离子体的分布、形成及磁鞘粒子进入磁层都具有重要启示作用; 同时发现并定义了一种新型分立极光结构—— 喉区极光, 并推断其可能对应磁层顶的局地变形。喉区极光是指发生在电离层对流喉区附近、从极光卵赤道侧向低纬方向延伸出来的分立极光结构。全天空极光观测表明喉区极光走向大致与电离层对流方向一致。之后, 观测验证了喉区极光对应磁层顶局地内陷式变形的推测; 统计发现喉区极光是一种非常高发的现象, 对应的磁层顶变形尺度可达2—3 Re, 并指出这种变形最可能由磁鞘高速流冲击磁层顶产生; 发现在喉区极光产生过程中还可能触发磁重联; 证实伴随喉区极光的产生, 磁鞘粒子会进入磁层并诱发产生一种新型弥散极光。通过喉区极光研究, 可以将已有的磁鞘瞬态过程研究和触发式磁重联研究有机地结合在一起, 对太阳风-磁层耦合过程形成一种新的认识, 即: 在磁鞘中局地产生(而不是存在于太阳风中)的瞬态过程可以在日下点附近频繁地导致磁层顶局地变形、触发重联、引发系列地球空间效应, 可能对太阳风-磁层耦合具有不可忽略的重要性。以此为基础, 讨论了日侧极光研究引出的新课题。

关键词: 极光, 弥散极光, 喉区极光

Abstract:

Recent results based on optical auroral observations at Yellow River Station are reviewed. A systematic study of dayside diffuse aurora has important implications for many topics, such as generation and distribution of cold plasmas in the dayside outer magnetosphere, and penetration of magnetosheath particles into the magnetosphere. We report a new auroral form, the “throat aurora”, and confirm it corresponds to localized magnetopause indentation using coordinated satellite and ground observations. The occurrence rate of throat aurora can be high, and the special scale of magnetopause indentation associated with it as large as 2–3 RE. We suggest that throat auroras are likely caused by a magnetosheath high-speed jet impacting on the magnetopause, and that they should be associated with magnetopause reconnection. We confirm that a special diffuse aurora can be generated from magnetosheath particle penetration into the magnetosphere associated with generation of throat aurora. We propose that transient structures locally generated in the magnetosheath (but not originating from solar wind) frequently cause indentations in the subsolar magnetopause, trigger reconnection, result in series of responses in geospace, and accordingly play an important role in solar wind-magnetosphere coupling.

Key words: aurora, dayside diffuse aurora, throat aurora