A tool for characterizing and evaluating Type II auroral arcs
Abstract
The paper is intended as a tool for describing or analyzing auroral arcs embedded in a Type II current system. The physics has been extensively described by analytical models in recent papers of the author. Here it is only briefly summarized to the extent needed to explain the set of relations describing the gross properties of embedded arcs. The equations are fully consistent with those derived in the earlier papers, but more general. A new element is the consideration of what determines the width of an auroral arc. Two solutions are presented depending on the relative contributions of the auroral acceleration process and ionospheric dissipation to the total energy conversion rate. It is argued that nature chooses the solution of optimum energy conversion. The equations are best suited to describe structured arcs in the evening auroral oval with inverted-V particle signature, even when they appear more dynamic than a quasi-static approach seems to allow. In spite of the inherent idealizations, the presented relations may prove to be useful for analyzing data from satellite transits through auroral current sheets.
- Publication:
-
Journal of Geophysical Research (Space Physics)
- Pub Date:
- June 2012
- DOI:
- 10.1029/2012JA017523
- Bibcode:
- 2012JGRA..117.6214H
- Keywords:
-
- Ionosphere: Auroral ionosphere (2704);
- Ionosphere: Particle acceleration;
- Magnetospheric Physics: Auroral phenomena (2407);
- Magnetospheric Physics: Field-aligned currents and current systems (2409);
- Magnetospheric Physics: Magnetosphere/ionosphere interactions (2431)