GEM: Fundamental Properties of Dawnside Auroral Polarization Streams and Their Role in Magnetosphere-Ionosphere Instabilities and Dramatic Events

University Of California-Los Angeles, Los Angeles CA

Investigators

Abstract

This work focuses on a unique phenomenon of a strong electric field that flows in Earth’s upper atmosphere (or ionosphere), called Dawnside Auroral Polarization Streams (DAPS). The DAPS is an essential component of the energy circulation of the near-Earth space environment and is related to the instabilities responsible for dramatic energy releases in the system. Occurring frequently, DAPS can significantly modify the ionosphere temperature and thus its composition and density, which impact the drag of low-altitude spacecraft and the scintillation of radio wave transmission. Aiming at understanding the formation and consequences of DAPS, this project will provide crucial information for advanced modeling of the near-Earth space environment and space weather prediction. This funded work will promote the development of an early-career scientist (the PI) and a very early-career female researcher. It will also involve undergraduate students interested in space physics as volunteers and for research course credit. This project involves auroral phenomena, so it naturally appeals to the general public. Appropriate materials from the products will be conveyed to the public (including K-12 students) via education and public outreach efforts. The strong southward electric field and associated eastward flow that extends within the Region 1 current portion of the auroral oval are referred to as the Dawnside Auroral Polarization Stream (DAPS). A DAPS’ strong electric field can significantly modify magnetosphere-ionosphere convection and energetic particle drift and heat the ionosphere and thermosphere. This project aims to determine fundamental DAPS properties and their impacts, including how DAPS vary under different conditions, what contributes to these variations, and their role in instabilities responsible for dramatic M-I events. The team will use low-altitude spacecraft observations (Swarm and DMSP) to measure a magnetic field vector and east-west flow, from which they can identify FAC structures and DAPS with automated methods. Applying these methods to ~20 years of data, the team will conduct comprehensive statistical studies to answer the questions. The research results will provide crucial information on DAPS’ generation mechanism and its impacts on the M-I system's convection, heating, and instability. The outcome of the studies will thus provide important implications for the M-I energy circulation. Given the frequent occurrence and strength of DAPS and their relationship to a major ionospheric conductivity change, the findings will likely be transformational for M-I-T modeling. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.