GEM: Source Processes for Dispersive Shear Alfven Waves

阿尔芬波似乎在电离层和磁层之间的能量耦合中起着重要作用。这个项目将研究产生这些波的过程。尽管它们很重要，但从航天器的现场观测中严格确定产生阿尔芬波的震源过程的情况很少。该项目将利用欧空局/美国航天局第二群组飞行任务的观测来确定这些过程，评估这些过程将能量转化为色散阿尔芬波的效率，并量化这些过程沉积到电离层的能量。这些波通过几种方式影响磁层和电离层之间的耦合：1)它们刺激从电离层流出的等离子体；2)它们将发生在外部磁层中的过程与电离层进行电动力学耦合；3)它们受到全球尺度现象的驱动，例如磁层顶上的重联和低纬边界层中的Kelvin-Helmholtz不稳定性。拟议的研究对地球空间大气环流模式(GGCM)的发展具有重要意义，因为它可以提供描述从这些过程到磁层和电离层的能量输入的经验性定律，这些定律可以并入全球磁流体力学程序。拟议的研究通过为学生研究人员提供支持来促进教学、培训和学习，学生研究人员将参与研究的各个方面。

Alfven waves appear to play an important role in the coupling of energy between the ionosphere and the magnetosphere. This project will examine the processes that produce these waves. Despite their importance rigorous identification of the source processes responsible for Alfven wave generation from in situ spacecraft observations are scarce. This project will employ observations from the ESA/NASA Cluster-II mission to identify these processes, evaluate the efficiency which energy is converted into dispersive Alfven waves by these processes, and quantify the energy that such processes deposit into the ionosphere. The waves affect the coupling between the magnetosphere and ionosphere in several ways: 1) they stimulate plasma outflow from the ionosphere, 2) they electrodynamically couple processes occurring in the outer magnetosphere to the ionosphere, and 3) they are driven by global-scale phenomena such as reconnection on the magnetopause and the Kelvin- Helmholtz instability in the low latitude boundary layer. The proposed research is important in the development of a Geospace General Circulation Model (GGCM) since it can provide empirically based laws describing the energy input from these processes into the magnetosphere and ionosphere which can be incorporated into global MHD codes. The proposed research promotes teaching, training and learning by providing support for a student researcher who will be involved in every aspect of the study.