Energetics of the Plasma Sheet

这个研究项目涉及对地球等离子体层的能量学和热力学的研究。所使用的方法是在先前的国家科学基金会资助下开发的。Geotail卫星数据用于生成一系列长期平均的等离子体层三维模型。一个系列中的每一个模型都是使用与特定地球物理条件相对应的数据产生的。这些模型可以表示在选定的太阳风和行星际磁场条件下，在选定的流速特征区域，在磁重联区域附近，在选定的亚暴阶段等条件下的等离子体片。每个基于数据的模型都包含了磁场和几百个离子和电子等离子体参数的三维信息。新的粒子和场参数是电子和离子的热流、玻尔兹曼熵和与十二个能带相关的部分密度。热通量以前没有包括在基于等离子体片的三维数据模型中。它们在产生场向电流和等离子体层与电离层之间的能量流动中起着重要作用。玻尔兹曼熵是一个新的参数，将与我们之前研究的熵参数进行比较。熵参数之间的差异是由分布函数的非麦克斯韦特征和通量管中粒子的损失引起的。测量的等离子体和磁场参数的模型，除其他外，可用于研究等离子体的不稳定性，与全球磁层模拟进行比较，并作为全球环境和空间天气模型预测的测试。空间天气和环境模拟项目预计将对通信问题产生重要影响，这将使更广泛的人口感兴趣。基于三维数据的模型的可用性在规划未来的卫星任务方面可能是有用的。

This research project involves a study of the energetics and thermodynamics of the Earth's plasma sheet. The methods to be used were developed with support from a prior NSF grant. Geotail satellite data is used to generate a series of long term averaged three-dimensional models of the plasma sheet. Each model in a series is produced using only data corresponding to a specific geophysical condition. The models can represent the plasma sheet under selected solar wind and interplanetary magnetic field conditions, in regions characterized by selected flow velocities, near magnetic reconnection regions, during selected substorm phases, etc. Each data based model includes 3-D information about both the magnetic field and about each of several hundred ion and electron plasma parameters. The new particle and field parameters the electron and ion heat fluxes, Boltzmann entropies, and partial densities associated with twelve energy bands. Heat fluxes have not previously been included in 3-D data based models of the plasma sheet. They play an important role in the generation of the field aligned currents and the flow of energy between the plasma sheet and the ionosphere. The Boltzmann entropy is a new parameter that will be compared to the entropy parameters investigated in our earlier studies. Differences between the entropy parameters are caused by non-Maxwellian features of the distribution functions and by the loss of particles from flux tubes. Models of the measured plasma and field parameters can be used, among other things, to study plasma instabilities, to compare with global magnetospheric simulations, and as a test of global environmental and space weather model predictions. Space weather and environmental modeling programs are expected to have an important impact on communications issues that will be of interest to a much broader population. The availability of 3-D data based models is potentially useful in the planning of future satellite missions.