行星际磁场时钟角与地球磁层开放磁通的关系  

Relationship between Interplanetary Magnetic Field Clock Angle and Magnetosphere Open Magnetic Flux

作　　者：夏之阳 王赤[2] 彭忠[2] 陆全明[1] 

机构地区：[1]中国科学技术大学地球和空间科学学院,合肥230026 [2]中国科学院空间科学与应用研究中心空间天气学国家重点实验室,北京100190

出　　处：《空间科学学报》2014年第1期24-28,共5页Chinese Journal of Space Science

基　　金：国家自然科学基金项目(41231067;41004073);国家重点基础研究发展计划项目(2012CB825602);科技部国家重点实验室专项经费共同资助

摘　　要：地球磁层开放磁通F_(pc)是研究磁层动力学过程的重要参数之一,其与日侧和夜侧磁尾的磁场重联具有密切关系.日侧重联率控制稳定状态下磁层开放磁通的大小,主要受各种太阳风条件的影响.其中,行星际磁场(IMF)的时钟角是影响日侧重联率的一个重要因素.通过全球MHD模拟,研究了行星际磁场时钟角θ_c与地球磁层开放磁通F_(pc)之间的关系.结果表明,开放磁通F_(pc)随着行星际磁场时钟角θ_c逐渐接近180°(纯南向)而逐渐增加,两者之间的关系近似为F_(pc)∝sin^(3/2)(θ_c/2).由于表征行星际磁场与地球磁场剪切程度的θ_c影响日侧重联率,从而控制F(pc),该关系反映了二者之间的物理联系.The open magnetic flux （Fpc） is a key parameter to study magnetospheric dynamical process, which is closely related to magnetic reconnections in the dayside magnetopause and mag- netotail. The dayside reconnection rate controls the amount of the open magnetic flux, which is affected by various solar wind parameters, among which the clock angle θc of the interplanetary magnetic field （IMF） is an important factor that influence the dayside reconnection rate. Using global MHD simulations, we analyze the relationship between θc and Fpc. The results show that the open flux Fpc increases as the clock angle θc approaches 180°（due southward）, and the open flux Fpc is proportional to sin3/2（θc/2）. This reflects the physical connection between them, sinceθc describes the magnitude of the shear between IMF and terrestrial magnetic field, and affects the dayside reconnection rate, thus controlling the open flux Fpc.

关 键 词：开放磁通 行星际磁场时钟角 MHD模拟 

分 类 号：P353[天文地球—空间物理学]