Spatial-temporal characteristics of flickering spots in flickering auroras.

Kunitake, Manabu; Oguti, Takasi

doi:10.5636/jgg.36.121

Cited by 29 publications

(40 citation statements)

References 15 publications

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“…[4] Flickering aurora has been typically reported to have a temporal fluctuation in the frequency range from 5 to 15 Hz [Beach et al, 1968;Berkey et al, 1980;Kunitake and Oguti, 1984;Sakanoi and Fukunishi, 2004;Whiter et al, 2008]. This frequency range is consistent with the O + ion cyclotron frequency at altitudes of several thousand kilometers.…”

Section: Introductionsupporting

confidence: 62%

“…Holmes et al [2005aHolmes et al [ , 2005b and Whiter et al [2008] found the smallest scale size for the flickering spots of less than 1 km. These spots are sometimes observed associated with both rapid drifting and rotating features [Kunitake and Oguti, 1984;Gustavsson et al, 2008]. The typical amplitude of the periodic luminosity modulation has been reported as 10-20% of the total intensity of background auroral arcs [Kunitake and Oguti, 1984;Sakanoi and Fukunishi, 2004;Gustavsson et al, 2008].…”

Section: Introductionmentioning

confidence: 99%

“…[3] A typical flickering spot has a spatial scale of 1-12 km with 1-2 s lifetime [Beach et al, 1968;Kunitake and Oguti, 1984;McFadden et al, 1987;Sakanoi and Fukunishi, 2004]. Holmes et al [2005aHolmes et al [ , 2005b and Whiter et al [2008] found the smallest scale size for the flickering spots of less than 1 km.…”

Section: Introductionmentioning

confidence: 99%

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Spatial-temporal characteristics of flickering aurora as seen by high-speed EMCCD imaging observations

et al. 2011

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[1] We conducted high-speed imaging observations of flickering aurora at 100 Hz sampling rate using electron multiplying charge-coupled device in Alaska during 2009-2010 winter season. We detected various types of flickering aurora, including drifting and rotating features at a frequency below 15 Hz. We identified, for the first time, flickering stripes and some other unusual flickering events at frequency of higher than 20 Hz on the imaging observations. A dispersion relation derived from a statistical analysis of observed images is compared with the theoretical dispersion curve of O + electromagnetic ion cyclotron (EMIC) waves. The frequencies and spatial scales calculated from a coherence/phase analysis based on an interference theory are consistent with the wave dispersion relation derived from the statistical analysis, suggesting that the obtained results are essentially consistent with the scenario that the interference of EMIC waves produces the observed dispersion relation of flickering aurora. Furthermore, flickering frequencies higher than 20 Hz are confirmed from our observations, which are higher than expected frequency of O + EMIC waves at altitudes of several thousand kilometers. We therefore suggest that high-frequency waves such as He + and H + EMIC waves may also contribute to produce a significant fraction of flickering aurora.

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Section: Introductionsupporting

confidence: 62%

Section: Introductionmentioning

confidence: 99%

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Spatial-temporal characteristics of flickering aurora as seen by high-speed EMCCD imaging observations

et al. 2011

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“…The flickering spots are actually laterally vibrating columns of luminosity which tend to occur on the bottom edges of auroral arcs, Kunitake and Oguti [1984]. The size of the flickering column normally extends 1-5 km transverse to the magnetic field, [Beach et al 1969; Kunitake and Oguti 1984;McFadden et al 1987]. The flicker frequency is typically between 2-20 Hz, [Beach et al 1969;McFadden et al 1987], and the lifetime a few seconds, with several such columns occurring within a small area over the period of a few minutes, Kunitake and Oguti [1984].…”

Section: Introductionmentioning

confidence: 99%

Fast photometry of flickering in discrete auroral arcs

McHarg

Hampton²,

Stenbaek‐Nielsen³

1998

Geophysical Research Letters

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“…Flickering aurora consists of small-scale columns (1 to 12 km width and 10 to 40 km height) with periodic intensity variations (3 to 15 Hz) in discrete auroral arcs and is often observed associated with auroral breakup events (Kunitake and Oguti 1984). Temerin et al (1986Temerin et al ( , 1993 suggested that electromagnetic ion cyclotron (EMIC) waves that occur below the inverted-V acceleration region can accelerate and modulate the field-aligned electrons over a broad energy range to produce flickering aurora.…”

Section: Introductionmentioning

confidence: 99%

Compound auroral micromorphology: ground-based high-speed imaging

Kataoka

Fukuda

Miyoshi

et al. 2015

Earth, Planets and Space

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Auroral microphysics still remains partly unexplored. Cutting-edge ground-based optical observations using scientific complementary metal-oxide semiconductor (sCMOS) cameras recently enabled us to observe the fine-scale morphology of bright aurora at magnetic zenith for a variety of rapidly varying features for long uninterrupted periods. We report two interesting examples of combinations of fine-scale rapidly varying auroral features as observed by the sCMOS cameras installed at Poker Flat Research Range (PFRR), Alaska, in February 2014. The first example shows that flickering rays and pulsating modulation simultaneously appeared at the middle of a surge in the pre-midnight sector. The second example shows localized flickering aurora associated with growing eddies at the poleward edge of an arc in the midnight sector.

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Spatial-temporal characteristics of flickering spots in flickering auroras.

Cited by 29 publications

References 15 publications

Spatial-temporal characteristics of flickering aurora as seen by high-speed EMCCD imaging observations

Spatial-temporal characteristics of flickering aurora as seen by high-speed EMCCD imaging observations

Fast photometry of flickering in discrete auroral arcs

Compound auroral micromorphology: ground-based high-speed imaging

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