日侧弥散极光对太阳风动压增强的响应  

DAYSIDE DIFFUSE AURORA RESPONSE TO AN INCREASE SOLAR WIND DYNAMIC PRESSURE

作　　者：陈相材[1,2] 韩德胜[1] 胡泽骏[1] 刘建军[1,3] 胡红桥[1] 邢赞扬[1,4] 刘俊明[1] 刘瑞源[1] 

机构地区：[1]中国极地研究中心国家海洋局极地科学重点实验室,上海200136 [2]内蒙古师范大学物理与电子信息学院,内蒙古呼和浩特010022 [3]武汉大学电子信息学院,湖北武汉430070 [4]西安电子科技大学理学院,陕西西安710071

出　　处：《极地研究》2012年第3期274-283,共10页Chinese Journal of Polar Research

基　　金：国家自然科学基金项目(40974083;41031064;40974103;40904041;40890164);海洋公益性行业科研专项(201005017);海洋局青年基金重点项目(2010613);南北极环境综合考察与评估专项(CHINARE2012-02-03)资助

摘　　要：太阳风动压的显著变化能导致沉降进入极区电离层的能量粒子通量以及磁层-电离层电流系发生扰动。磁层高能粒子沉降到极区高层大气并与中性气体碰撞激发的弥散极光,能够对这种扰动做出相应的响应。基于斯瓦尔巴特(Svalbard)群岛新奥尔松(Ny-lesund)地区北极黄河站优越的地理优势,利用安装在黄河站的极光全天空成像仪观测到了日侧弥散极光对太阳风动压增强的响应。通过2006年1月2日事件观测显示,随着太阳风动压的增强,日侧弥散极光在极光卵赤道侧部分首先点亮并逐渐向高纬扩展,同时地磁环境也受到相应扰动影响。我们认为,随着太阳风动压的增强,日侧磁层顶受到压缩,磁层内波粒相互作用导致投掷角散射增强,使得沉降进入极光卵赤道侧电离层的高能粒子数密度增大,进而导致日侧弥散极光强度增强。The sudden enhancement of solar wind dynamic pressure can result in the disturbance on the flux of energetic particles precipitating into the ionosphere and the current intensity in magnetosphere-ionospheric current system. The diffuse aurora, which is excited by high-energy particles of magnetosphere precipitating into the upper atmosphere and impacting with the neutral gas, can respond to the disturbance. Because of the location of Yellow River Station （YRS） in Ny-？lesund, Svalbard is good for the optical observation of dayside aurora. A case of the dayside diffuse aurora was observed by the all-sky imager （ASI） in YRS, which intensively responds to a variety of solar wind dynamic pressure. With the enhancement of the solar wind dynamic pressure, the diffuse aurora on the equatorward of ASI’s field-of-view showed the intensity enhance and the poleward extension on latitude, the geomagnetic environment also showed a corresponding disturbance at the same time. We suggested that the dayside magnetopause is compressed because of the enhancement of the solar wind dynamic pressure. It can result in the enhancement of pitch-angle scatter by wave particle interaction in the magnetosphere. Consequently, the number flux of the high-energy particle scattering the loss-cone and precipitating into the equatorward ionosphere of auroral oval is enhanced, and led the emission increase of dayside diffuse aurora.

关 键 词：日侧弥散极光 行星际磁场 太阳风动压 地磁活动 

分 类 号：P353[天文地球—空间物理学]