Magnetohydrodynamic simulation of interaction between the solar-wind magnetosphere, and ionosphere

本文建立了一个自洽处理太阳风-磁层-电离层相互作用的三维全球磁流体动力学（MHD）模型，并研究了其传输过程。太阳风和行星际磁场（IMF）的变化对地球磁层的结构和动力学产生了强烈的影响。磁层上的直接驱动过程（如极电势）对它们的变化大约在10分钟内作出响应，而等离子体片中的加载-卸载过程（如尾部重联的开始）通常需要大约1小时的时间延迟，因此，为了获得未来的磁层结构，需要知道当前的磁层结构以及太阳风和IMF的参数磁层和电离层耦合是地球物理过程中的重要过程之一。为了将电离层反馈过程纳入到全球磁流体动力学模型中， 关于我们 在模拟太阳风-磁层相互作用时，传统的方法是将场向电流从磁层内边界映射到电离层上，通过考虑电离层电导率计算极地电离层中的电势，然后将对流电场映射到磁层内。我们在全球MHD模拟中尝试了相反的过程，对1996年11月17日的太阳风与地球磁层相互作用进行了三维全球MHD模拟，并对1999年3月19-20日的空间天气“电喷流挑战”事件进行了研究。作为模拟的输入，利用了WIND和ACE卫星提供的太阳风参数的一分钟值，即太阳风速度的x分量、太阳风密度、等离子体压力以及太阳磁层坐标中IMF的y分量和z分量。我们提出了横截面的能量分布在中午午夜和赤道平面，极坐标图的电离层电位和配置的磁场线每10分钟与卫星和SuperDARN的观测进行比较。少

We have constructed a 3-dimensional global magnetohydrodynamic (MHD) model to self-consistently treat the solar wind-magnetosphere-ionosphere interaction, and have studied the transfer processes. Configuration and dynamics of the earth's magnetosphere are strongly affected by variations of the solar wind and interplanetary magnetic field (IMF) for recent several hours. Directly driven process on the magnetosphere like a polar electric potential responds in about 10 minutes to their variations, on the other hand loading-unloading precess like onset of tail reconnection in the plasma sheet usually needs about 1 hour time delay from sudden southward turn of IMF.Therefore, it is necessary to know the present magnetospheric configuration as well as the present parameters of the solar wind and IMF in order to obtain future magnetospheric configuration.Magnetosphere and ionosphere coupling is one of important processes. In order to include the ionospheric feedback process to the global MHD si … More mulation of the solar wind-magnetosphere interaction, field aligned currents are traditionally mapped from the inner boundary of magnetosphere onto the ionosphere, electric potential is calculated in the polar ionosphere by including ionospheric conductivity, and then convective electric fields are reversely mapped to the inner magnetosphere. We have tried the opposite procedure in our global MHD simulation.A 3-dimensional global MHD simulation of the interaction between the solar wind and the earth's magnetosphere has been executed to study the event of November 17, 1996 and the space weather "electrojet challenge" event of March 19-20, 1999. As input for the simulation, one minute values of solar wind parameters from the WIND and ACE satellites were utilized, namely the x-component of the solar wind velocity, the solar wind density, the plasma pressure and the y-and z-components of the IMF in solar-magnetospheric coordinates. We presented cross sectional profiles of energy in the noon-midnight and equatorial planes, polar plots of ionospheric potential and configuration of magnetic field lines every 10 minutes to compare with the satellite and SuperDARN observations. Less