Interaction Between Proton Aurora and Stable Auroral Red Arcs Unveiled by Citizen Scientist Photographs
Abstract
We utilized citizen scientist photographs of subauroral emissions in the upper atmosphere and identified a repeatable sequence of proton aurora and subauroral red (SAR) arc during substorms. The sequence started with a pair of green diffuse emissions and a red arc that drifted equatorward during the substorm expansion phase. Simultaneous spectrograph and satellite observations showed that they were subauroral proton aurora, where ion precipitation created secondary electrons that illuminated aurora in green and red colors. The ray structures in the red arc also indicated existence of low‐energy electron precipitation. The green diffuse aurora then decayed but the red arc (SAR arc) continued to move equatorward during the substorm recovery phase. This sequence suggests that the SAR arc was first generated by secondary electrons associated with ion precipitation and may then transition to heat flux or Joule heating. Proton aurora provides observational evidence that ion injection to the inner magnetosphere is the energy source for the initiation of the SAR arc.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jul 01, 2022
- Source ID
- 10.1029/2022ja030570
Entities
People
- Alan Dyer
- Carlos Martinis
- E. Bruus
- Eero Karvinen
- Eric Donovan
- H. K. Rikala
- J. M. Ruohoniemi
- L. Kangas
- Nozomu Nishitani
- Yukitoshi Nishimura
Organizations
- Air Force Office of Scientific Research
- Boston University
- Nagoya University
- National Aeronautics and Space Administration
- National Science Foundation
- University of Calgary
- Virginia Tech