The Occurrence of Embedded Region 1 and 2 Currents Depends on Geomagnetic Activity Level
Abstract
Embedded Region 1 and 2 field‐aligned currents (FACs), intense FAC layers of mesoscale latitudinal width near the interface between large‐scale Region 1 and Region 2 FACs, are related to dramatic phenomena in the ionosphere such as discrete arcs, inverted‐V precipitation, and dawnside auroral polarization streams. These relationships suggest that the embedded FACs are potentially important for understanding ionospheric heating and magnetosphere‐ionosphere (M‐I) coupling and instabilities. Previous case studies of embedded FACs have led to the speculation that they may result from enhanced M‐I convection during active times. To explore this idea further, we investigate statistically their occurrence rates under a variety of geomagnetic conditions with a large event list constructed from 17 years of Defense Meteorological Satellite Program observations. The identification procedure is fully automated and explicit. The statistical results indicate that embedded Region 1 and 2 FACs are common, and that they have a higher chance to occur when the level of geomagnetic activity is higher (given by various indices), supporting the idea that they result from enhanced M‐I convection.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Nov 01, 2022
- Source ID
- 10.1029/2022ja030539
Entities
People
- Chih-Ping Wang
- J. Wu
- Jiang Liu
- Larry R Lyons
- Shinichi Ohtani
- T. Higuchi
- Vassilis Angelopoulos
- Ying Zou
Organizations
- Air Force Office of Scientific Research
- Johns Hopkins University Applied Physics Laboratory
- National Aeronautics and Space Administration
- National Science Foundation
- The Institute of Statistical Mathematics
- University of Alabama
- University of Calgary