AGS-PRF: Dayside Field Aligned Currents and Energy Deposition: The Effect of Magnetospheric Structure and Ionospheric Conductivity

Wilder Frederick D, Virginia Beach VA

Investigators

Abstract

This project will examine intense dayside field-aligned currents(FACs) in Earth's magnetosphere. These intense FACS occur when the interplanetary magnetic field is strong a lies primarily in the ecliptic plane. In particular the project will examine the occurrence of these currents when the component of the magnetic field perpendicular to the ecliptic plane is upward (positive IMF Bz). These FACs have been shown to be associated with extreme levels of ionospheric Joule heating and Poynting flux, which leads to upwelling of ionospheric plasma and anomalous thermospheric density enhancements. Maps of field-aligned current intensity, ionospheric joule heating, and the polar cap potential pattern will be related to the magnetospheric field-line topology as well as upstream and magnetosheath solar wind driving conditions and plasma parameters. The following scientific questions will be addressed: (1) how is the magnitude of these currents affected by the magnetic topology of the magnetosphere? (2) is the source of the current magnetic merging at the dayside magnetopause or is it due to surface currents at the bow shock? (3) how does the conductivity of the ionosphere (including seasonal effects) affect the magnitude of the FACs, the Joule heating and the Poynting flux. These questions will be addressed using a large variety of ground-based and space-based data. The questions that will be addressed in this project will provide new understanding of important space weather effects that take place under conditions that are generally considered to be magnetically quiet. In particular the project will improve our understanding of the effects these strong currents have on enhancing thermospheric upwelling, which leads to increased satellite drag. The research will be primarily conducted by a recent PhD graduate.