On the Asymmetry Between Upward and Downward Field‐Aligned Currents Interacting With the Ionosphere
Abstract
The paper presents results from the numerical study of the magnetosphere‐ionosphere interactions driven by the large‐scale electric field in the magnetically conjugate, high‐latitude regions of northern and southern hemispheres. Simulations of the two‐fluid MHD model demonstrate that these interactions can lead to a generation of a system of small‐scale, intense field‐aligned currents with a significant difference in size and amplitude between the upward and downward currents. In particular, in both hemispheres, the downward currents (where the electrons are flowing from the ionosphere) become more narrow and intense than the adjacent upward currents. At high latitudes, the field‐aligned currents are closely related to the discrete auroral arcs. The fact that this mechanism produces very narrow and intense downward currents embedded into the broader upward current regions makes it relevant to the explanation of the “black” auroral arcs appearing as narrow, dark strips embedded in the broad luminous background.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Nov 01, 2018
- Source ID
- 10.1029/2018ja025826
Entities
People
- A. V. Streltsov
Organizations
- Air Force Research Laboratory
- Embry–Riddle Aeronautical University
- National Academies of Sciences, Engineering, and Medicine
- National Academy of Sciences