The Lyman-Birge-Hopfield bands in aurora

Dashkevich, Zh. V.; Sergienko, T.; Иванов, В. Э.

doi:10.1016/0032-0633(93)90019-x

Cited by 15 publications

(5 citation statements)

References 11 publications

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“…Panels where the downward NBZ cell dominates are devoid of NBZ‐associated auroral emission. This is consistent with the appearance of the auroral emissions within the LBHl band, which are mainly driven by electron precipitation, for example, Dashkevich et al (). However, other authors have noted that a substantial percentage of LBHl emission as detected by SUSSI may be driven by proton precipitation (Knight et al, ).…”

Section: Resultssupporting

confidence: 89%

The Association of High‐Latitude Dayside Aurora With NBZ Field‐Aligned Currents

et al. 2018

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The relationship between auroral emissions in the polar ionosphere and the large-scale flow of current within the Earth's magnetosphere has yet to be comprehensively established. Under northward interplanetary magnetic field (IMF) conditions, magnetic reconnection occurs at the high-latitude magnetopause, exciting two reverse lobe convection cells in the dayside polar ionosphere and allowing ingress of solar wind plasma to form an auroral "cusp spot" by direct impact on the atmosphere. It has been hypothesized that a second class of NBZ auroras, High-latitude Dayside Aurora, are produced by upward field-aligned currents associated with lobe convection. Here we present data from the Special Sensor Ultraviolet Spectrographic Imager instrument and from the Active Magnetosphere and Planetary Electrodynamics Response Experiment, from January 2010 to September 2013, in a large statistical study. We reveal a northward IMF auroral phenomenon that is located adjacent to the cusp spot and that is colocated with a region of upward electrical current in the clockwise-rotating lobe cell. The emission only occurs in the sunlit summer hemisphere, demonstrating the influence of the conductance of the ionosphere on current closure. In addition, fast solar wind speed is required for this emission to be bright. The results show that dayside auroral emission is produced by IMF-magnetosphere electrodynamic coupling, as well as by direct impact of the atmosphere by the solar wind, confirming the association of High-latitude Dayside Aurora with NBZ currents. Plain Language SummaryUnder certain incoming solar wind conditions, patches of aurora are sometimes found not in the main bright auroral oval but inside the normally otherwise dark polar cap region. These patches of auroral emissions are colocated with regions of upward flowing electrical current. We present a study of these emissions using nearly 3 years of data from both the North and South Hemispheres, combining simultaneous observations of the polar cap at ultraviolet wavelengths, and measurements of field-aligned currents. This builds on the previous work of other authors, who observed these auroral emissions in the Northern Hemisphere only. The upward current associated auroral emissions occur when the incoming interplanetary magnetic field is northward and are shown to only be observable in the summer hemisphere. This implies a dependence on the conductance of the ionosphere, via photoionization, on the appearance of these auroras.

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Section: Resultssupporting

confidence: 89%

The Association of High‐Latitude Dayside Aurora With NBZ Field‐Aligned Currents

et al. 2018

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“…While the populations observed may not match direct (X -+ a) excitation, it is the only process included in the models which have been used for dayglow calculations. Radiative cascade between the singlet states was included in the auroral modeling presented by Cartwright [1978] and by Dashkevich et al [1993], but both fail to match observations of the aurora or dayglow. Radiative cascade between singlet states should be significant based on the transition rate data, which indicate that radiative transitions between the singlet states of N2 are only a factor of -•5 slower than the a-+ X transitions [e.g., Gilmore et al, 1992;MarineIll et al, 1989].…”

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confidence: 99%

Modeling the N₂ Lyman‐Birge‐Hopfield bands in the dayglow: Including radiative and collisional cascading between the singlet states

Eastes¹

2000

J. Geophys. Res.

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“…The wide-field auroral imager (WAI) is designed for studying the dynamics of auroras and potentially for forecasting auroral substorms by imaging the N 2 Lyman–Birge–Hopfield (LBH) auroral bands. The LBH aurora is generated by the collision with the molecular nitrogen of the energetic electron precipitating into the polar upper atmosphere along the Earth’s magnetic field lines 1,2 . The intensity of the auroral LBH emissions depends on the flux and mean energy of the precipitated electrons and the mixed auroral boundary.…”

Section: Introductionmentioning

confidence: 99%

Wide-field auroral imager onboard the Fengyun satellite

Zhang

Chen

et al. 2019

Light Sci Appl

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The newly launched Fengyun-3D (FY-3D) satellite carried a wide-field auroral imager (WAI) that was developed by Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences (CIOMP), which will provide a large field of view (FOV), high spatial resolution, and broadband ultraviolet images of the aurora and the ionosphere by imaging the N 2 LBH bands of emissions. The WAI consists of two identical cameras, each with an FOV of 68° in the along-track direction and 10° in the cross-track direction. The two cameras are tilted relative to each other to cover a fan-shaped field of size 130° × 10°. Each camera consists of an unobstructed four-mirror anastigmatic optical system, a BaF 2 filter, and a photon-counting imaging detector. The spatial resolution of WAI is ~10 km at the nadir point at a reference height of 110 km above the Earth’s surface. The sensitivity is >0.01 counts s −1 Rayleigh −1 pixel −1 (140–180 nm) for both cameras, which is sufficient for mapping the boundaries and the fine structures of the auroral oval during storms/substorms. Based on the tests and calibrations that were conducted prior to launch, the data processing algorithm includes photon signal decoding, geometric distortion correction, photometric correction, flat-field correction, line-of-sight projection and correction, and normalization between the two cameras. Preliminarily processed images are compared with DMSP SSUSI images. The agreement between the images that were captured by two instruments demonstrates that the WAI and the data processing algorithm operate normally and can provide high-quality scientific data for future studies on auroral dynamics.

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The Lyman-Birge-Hopfield bands in aurora

Cited by 15 publications

References 11 publications

The Association of High‐Latitude Dayside Aurora With NBZ Field‐Aligned Currents

The Association of High‐Latitude Dayside Aurora With NBZ Field‐Aligned Currents

Modeling the N₂ Lyman‐Birge‐Hopfield bands in the dayglow: Including radiative and collisional cascading between the singlet states

Wide-field auroral imager onboard the Fengyun satellite

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The Lyman-Birge-Hopfield bands in aurora

Cited by 15 publications

References 11 publications

The Association of High‐Latitude Dayside Aurora With NBZ Field‐Aligned Currents

The Association of High‐Latitude Dayside Aurora With NBZ Field‐Aligned Currents

Modeling the N2 Lyman‐Birge‐Hopfield bands in the dayglow: Including radiative and collisional cascading between the singlet states

Wide-field auroral imager onboard the Fengyun satellite

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Product

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Modeling the N₂ Lyman‐Birge‐Hopfield bands in the dayglow: Including radiative and collisional cascading between the singlet states