EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Characteristics of Fragmented Aurora-like Emissions (FAEs)

Joshua Dreyer1,2, Noora Partamies3,4, Daniel Whiter5, Pål G. Ellingsen6, Lisa Baddeley3,4, and Stephan C. Buchert1
Joshua Dreyer et al.
  • 1Swedish Institute of Space Physics, Space Plasma Physics, Uppsala, Sweden (
  • 2Department of Physics and Astronomy, Uppsala University, Uppsala, Sweden
  • 3Department of Arctic Geophysics, The University Centre in Svalbard, Longyearbyen, Norway
  • 4Birkeland Centre for Space Science, University of Bergen, Bergen, Norway
  • 5Department of Physics and Astronomy, University of Southampton, Southampton, UK
  • 6Department of Electrical Engineering, UiT – The Arctic University of Norway, Narvik, Norway

We present observations of a new type of small-scale aurora-like feature, which is further referred to as fragmented aurora-like emission(s) (FAEs).

They seem to appear in two categories – randomly occurring individual FAEs and wave-like structures with regular spacing between FAEs alongside auroral arcs. FAEs show horizontal sizes typically below 20 km, a lack of field-aligned emission extent, and short lifetimes of less than a minute. Emissions were observed at the 557.7 nm line of atomic oxygen and at 673.0 nm (N2; first positive band system) but not at the 427.8 nm emission of N2+ or the 777.4 nm line of atomic oxygen. This suggests an upper limit to the energy that can be produced by the generating mechanism. Their lack of field-aligned extent and 777.4 nm emissions indicates a different generation mechanism than for aurorae, which are caused by particle precipitation. Possible sources are Farley–Buneman instabilities or electrostatic ion cyclotron waves.

How to cite: Dreyer, J., Partamies, N., Whiter, D., Ellingsen, P. G., Baddeley, L., and Buchert, S. C.: Characteristics of Fragmented Aurora-like Emissions (FAEs), EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-5686,, 2022.


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