Lumikot: Fast Auroral Transients During the Growth Phase of Substorms

McKay, D. J.; Paavilainen, Tuula; Gustavsson, B.; Kvammen, Andreas; Partamies, Noora

doi:10.1029/2019gl082985

Cited by 4 publications

(1 citation statement)

References 20 publications

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“…Some open questions remain though, such as the intricacies of sudden changes in morphology and the drivers behind dynamic auroral processes (Karlsson et al, 2020). Small-scale features on the other hand are much less wellknown and new features are still being found, for example transient phenomena such as Lumikots (McKay et al, 2019).…”

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confidence: 99%

Fragmented Aurora-like Emissions (FAEs) as a new type of aurora-like phenomenon

Dreyer

Partamies²,

Whiter

et al. 2020

Preprint

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Abstract. This study analyses the observations of a new type of small-scale aurora-like feature, which is further referred to as Fragmented Aurora-like Emission(s) (FAEs). An all-sky camera captured these FAEs on three separate occasions in 2015 and 2017 at the Kjell-Henriksen Observatory near the arctic town of Longyearyben, Svalbard. A total of 305 FAE candidates were identified with varying degrees of certainty. 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 a limit to the energy of the generating mechanism. Their lack of field-aligned extent indicates a different generation mechanism than for aurora, which is caused by particle precipitation. Instead, these FAEs could be the result of excitation by thermal ionospheric electrons. FAE observations are seemingly accompanied by elevated electron temperatures between 110–120 km and increased ion temperatures at F-region altitudes. One possible explanation for this are Farley-Buneman instabilities of strong local currents. We provide an overview of the observations and discuss them as well as potential generation mechanisms in the present study.

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mentioning

confidence: 99%

Fragmented Aurora-like Emissions (FAEs) as a new type of aurora-like phenomenon

Dreyer

Partamies²,

Whiter

et al. 2020

Preprint

View full text Add to dashboard Cite

show abstract

Diffuse and Pulsating Aurora

et al. 2020

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This chapter reviews fundamental properties and recent advances of diffuse and pulsating aurora. Diffuse and pulsating aurora often occurs on closed field lines and involves energetic electron precipitation by wave-particle interaction. After summarizing the definition, large-scale morphology, types of pulsation, and driving processes, we review observation techniques, occurrence, duration, altitude, evolution, small-scale structures, fast modulation, relation to high-energy precipitation, the role of ECH waves, reflected and secondary electrons, ionosphere dynamics, and simulation of wave-particle interaction. Finally we discuss open questions of diffuse and pulsating aurora.

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Characteristics of fragmented aurora-like emissions (FAEs) observed on Svalbard

et al. 2021

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Abstract. This study analyses the observations of a new type of small-scale aurora-like feature, which is further referred to as fragmented aurora-like emission(s) (FAEs). An all-sky camera captured these FAEs on three separate occasions in 2015 and 2017 at the Kjell Henriksen Observatory near the arctic town of Longyearbyen, Svalbard, Norway. A total of 305 FAE candidates were identified. 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 indicates a different generation mechanism than for aurorae, which are caused by particle precipitation. Instead, these FAEs could be the result of excitation by thermal ionospheric electrons. FAE observations are seemingly accompanied by elevated electron temperatures between 110–120 km and increased ion temperatures at F-region altitudes. One possible explanation for this is Farley–Buneman instabilities of strong local currents. In the present study, we provide an overview of the observations and discuss their characteristics and potential generation mechanisms.

show abstract

Lumikot: Fast Auroral Transients During the Growth Phase of Substorms

Cited by 4 publications

References 20 publications

Fragmented Aurora-like Emissions (FAEs) as a new type of aurora-like phenomenon

Fragmented Aurora-like Emissions (FAEs) as a new type of aurora-like phenomenon

Diffuse and Pulsating Aurora

Characteristics of fragmented aurora-like emissions (FAEs) observed on Svalbard

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