The night when the auroral and equatorial ionospheres converged
Abstract
An all‐sky imaging system at the McDonald Observatory (30.67°N, 104.02°W, 40° magnetic latitude) showed dramatic ionospheric effects during a moderate geomagnetic storm on 1 June 2013. The auroral zone expanded, leading to the observation of a stable auroral red (SAR) arc. Airglow depletions associated with equatorial spread F (ESF) were also seen for the first time at such high magnetic latitude. Total electron content measurements from a Global Positioning System (GPS) receiver exhibited ionospheric irregularities typically associated with ESF. We explore why this moderate geomagnetic disturbance leads to such dramatic ionospheric perturbations at midlatitudes. A corotating interaction region‐like driver and a highly contracted plasmasphere caused the SAR arc to occur at L shell ~ 2.3. For ESF at L ~ 2.1, timing of the storm intensification, alignment of the sunset terminator with the central magnetic meridian, and sudden variations in the westward auroral electrojet all combined to trigger equatorial irregularities that reached altitudes of ~ 7000 km. The SAR arc and ESF signatures at the ionospheric foot points of inner magnetosphere L shells (L ~ 2) represent a dramatic convergence of pole to equator/equator to pole coupling at midlatitudes.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jan 16, 2015
- Source ID
- 10.1002/2015ja021555
Entities
People
- A. Coster
- Carlos Martinis
- J. Wroten
- John R. Baumgardner
- L. Paxton
- M. Mendillo
Organizations
- Boston University
- Johns Hopkins University
- Massachusetts Institute of Technology
- National Aeronautics and Space Administration
- National Science Foundation
- Office of Naval Research