GEM: Source Processes for Dispersive Shear Alfven Waves

University Of California-Berkeley, Berkeley CA

Investigators

Abstract

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.