Turbulent microstructures and formation of folds in auroral breakup arc

Ryuho Kataoka, Yoshizumi Miyoshi, Takeshi Sakanoi, Ayumi Yaegashi, Kazuo Shiokawa, Yusuke Ebihara

Research output: Contribution to journalArticlepeer-review

16 Citations (Scopus)


We conducted a ground-based optical measurement pointing at local magnetic zenith with a narrow field of view of 9.3 by 9.3, using a high-speed electron multiplier charge-coupled device camera at Poker Flat Research Range. We show evidence that auroral folds were periodically formed in a breakup arc and the luminosity is exponentially increased for about 10 s before an auroral breakup onset. The evolution of turbulent microstructures and the formation of folds may be interpreted by the nonlinear evolution of inertial Alfvén wave (IAW) turbulence in the thin current sheet. On the basis of these optical observations, we discuss a possible role of the ionosphere for modulating the triggering process of the onset via the self-organization of the IAW turbulence associated with Kelvin-Helmholtz and tearing instabilities of the thin current sheet.

Original languageEnglish
Article numberA00K02
JournalJournal of Geophysical Research: Space Physics
Issue number4
Publication statusPublished - 2011


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