行星际磁场北向期间太阳风-磁层能量耦合研究

The energy coupling between the solar wind and the magnetosphere is one of the most important aspects of magnetospheric physics, as the input energy leads to many space weather phenomena. It is well known that the Bz reconnection is the main mechanism when the IMF is directed southward. However, which is the main mechanism （viscous interaction, IMF|By| effects,etc）for the energy entry into the magnetosphere during northward IMFs remains a problem. Hence, quantitative studying the relative importance of different mechanisms in controlling the energy entry into the magnetosphere during the northward IMFs is of scientific significance to improve the solar wind-magnetosphere energy coupling mechanism.. In this project, we plan to select cases in the OMNI2 database from 1964 to 2011 when the IMF (in GSM coordinates) was mainly northward (> 5 nT) and lasted over 3 hours. By using the dimensional analysis and the multiple regression analysis, we plan to study the solar wind parameters dependence of the energy coupling during northwar IMFs and illustrate the relative importance of different mechanisms in controlling the energy entry into the magnetosphere. At last, we attempt to derive an energy coupling model during northward IMFs.

太阳风与磁层相互作用把能量传输到磁层，引起磁层内部一系列空间物理现象。Bz重联作为行星际磁场南向时太阳风向磁层传输能量的主要机制已经被广泛接受，然而在行星际磁场北向期间，何种机制 （如似粘滞，IMF |By|效应，等）起主要作用目前尚无定论。因此，定量研究行星际磁场北向期间各种机制在控制太阳风-磁层能量耦合效率过程中的贡献，对于进一步完善太阳风-磁层能量传输机制有重要的科学意义。.本项目拟利用OMNI2数据库1964-2011期间的太阳风数据，分析GSM坐标系下行星际磁场Bz > 5 nT、且持续时间超过3小时的北向事件，并结合同时期的地磁指数以及相应的卫星、极光和地磁台链数据。通过统计和理论分析，研究行星际磁场北向期间能量传输对太阳风参数的依赖性，在此基础上探讨何种机制在太阳风-磁层能量耦合过程中占主导作用，以期得到一个能够较好反映行星际磁场北向期间能量传输的耦和模型。