CAREER: Observational and Modeling Investigations of Pulsating Aurora Electrodynamics

Aurora is a high latitude phenomenon and is visible as arcs, sheets, curtains, etc. One common variety is referred to as pulsating aurora that includes on-and-off modulations. This spectacular feature results from the natural occurring emissions, and their intensity depends on precipitating electrons at high latitudes, which in turn can influence energy deposition.

Deposited energy can be propagated away in the form of gravity waves and can affect other latitudinal regions. Energetic particle precipitation associated with different aurora, and in particular pulsating aurora, can cause enhancements in the upper regions of the ionosphere, which absorbs high-frequency radio wave propagation. This impacts communication systems that are important for transpolar flights requiring continuous communication links to be open to the ground.

The focus of this investigation is specifically to understand pulsating aurora, which is one of the most observed auroral types. Despite its ubiquitous occurrence, the electrodynamics of pulsating aurora have not been investigated in detail as other kinds of aurora. This investigation intends to address fundamental problems associated with the electrodynamics of a time changing system, driven by the on-and-off modulations occurring during pulsating auroral events.

Educational efforts include a space science summer research experience for underrepresented minority (URM) middle school students and establishment of a NASA Rocksat-X program for undergraduate students at Clemson University. The activities will promote collaboration between academic (Clemson University) and non-academic, non-profit organization (Pisgah Astronomical Research Institute) and community partner (Littlejohn Community Center).

Enhanced electron precipitation during auroral events modifies ionospheric conductivity, and thus investigation of pulsating aurora offers an excellent opportunity to expand knowledge about electrodynamics of the high latitude regions. Two scientific questions that will be addressed as a part of this effort are (a) What is the electric field, current, and conductivity structure of pulsating aurora? and (b) How do temporal changes in the average energy and energy flux of the pulsating aurora precipitation affect the conductivity?

To address the first objective, the methodology will utilize Poker Flat incoherent scatter radar data and perform modeling investigations of pulsating aurora electrodynamics using the 3-D Geospace Environment Model of Ion-Neutral Interactions (GEMINI) ionosphere model. The GEMINI modeling simulations will be conducted on idealized pulsating aurora and actual events in which all-sky imager and PFISR data will be used to drive the model.

To achieve the second goal, utilization of the Poker Flat DPS-4D Digisonde, all-sky imager observations, and deployment of high frequency (HF) radio receivers and transmitters at Poker Flat Research Range are suggested. Additionally, a new technique will be developed that will leverage HF radio wave observations at high temporal resolution to capture fast ionospheric and associated electrodynamical changes occurring during the pulsating aurora.

This project is jointly funded by Aeronomy program, in the AGS Division of the GEO directorate and the Established Program to Stimulate Competitive Research (EPSCoR) at the NSF.

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.