TitlePolar cap arcs: Sun-aligned or cusp-aligned?
Publication TypeJournal Article
Year of Publication2016
AuthorsZhang, Y, Paxton, LJ, Zhang, Q, Xing, Z
JournalJournal of Atmospheric and Solar-Terrestrial Physics
Pagination123 - 128
Date Published08/2016
KeywordsPolar cap arcs Cusp Reconnection Kelvin Helmholtz Instability Velocity shear Field aligned current

Polar cap arcs are often called sun-aligned arcs. Satellite observations reveal that polar cap arcs join together at the cusp and are actually cusp aligned. Strong ionospheric plasma velocity shears, thus field aligned currents, were associated with polar arcs and they were likely caused by Kelvin–Helmholtz waves around the low-latitude magnetopause under a northward IMF Bz. The magnetic field lines around the magnetopause join together in the cusp region so are the field aligned currents and particle precipitation. This explains why polar arcs are cusp aligned.

Short TitleJournal of Atmospheric and Solar-Terrestrial Physics

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