NSWP: Space Weather--Further Development of Empirical Models of Plasma Densities in Near-Earth Magnetosphere

该项目将利用IMAGE卫星上的无线电等离子体成像仪（RPI）的数据，研究近地磁层（等离子层、亚极光/极光和极帽区）的等离子体密度分布和动力学。RPI的主动无线电探测提供了本地等离子体共振和远程反射信号（回声），可用于在卫星位置上获得原位等离子体密度，并远程和即时地获得低至约3000公里高度的磁场线密度分布。在不同地磁活动下，RPI数据库已累积了约100万次测量数据，涵盖了从约3000公里至4re高度的所有当地时间，并且数据库仍在不断增长。这使得开发经验密度模型成为可能，作为径向距离、纬度、当地时间、季节、太阳风/行星际磁场（IMF）条件和地磁活动指数的函数。RPI经验模型将与国际参考电离层（IRI）的上层密度剖面进行比较。统计和事件观测，以及数值模拟，将被用来提供对平均密度分布和实际事件的等离子体动力学的见解。

This project will study plasma density distributions and dynamics in the near-earth magnetosphere (plasmasphere, sub-auroral/auroral and polar cap region) by using data from the Radio Plasma Imager (RPI) on the IMAGE satellite. The active radio sounding of the RPI provides local plasma resonances and remotely reflected signals (echoes) that can be used to derive plasma densities in-situ at satellite locations, and remotely and instantaneously the density distributions along the magnetic field lines down to the altitude as low as approximately 3000 km. The RPI database has accumulated about one million measurements covering all local times from about 3000 km to 4 Re altitude under different geomagnetic activities and the database is still growing. This makes it possible to develop empirical density models as function of radial distance, latitude, local time, season, solar wind/interplanetary magnetic field (IMF) conditions, and geomagnetic activity indices. The RPI empirical models will be compared with topside density profiles from the International Reference Ionosphere (IRI). The statistical and event observations, as well as numerical simulations, will be utilized to provide insights to the plasma dynamics both for the average density distributions and actual events.