Open AccessA tool for characterizing and evaluating Type II auroral arcs
Author(s) -
Haerendel Gerhard
Publication year - 2012
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2012ja017523
Subject(s) - ionosphere , dissipation , physics , satellite , set (abstract data type) , arc (geometry) , geophysics , type (biology) , energy (signal processing) , current (fluid) , acceleration , defense meteorological satellite program , process (computing) , computer science , computational physics , meteorology , classical mechanics , geometry , mathematics , geology , quantum mechanics , astronomy , thermodynamics , programming language , operating system , paleontology
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.