Exploring the Upper Atmosphere

Paxton, L. J.; Zhang, Yongliang; Kil, H.; Schaefer, R. K.

doi:10.1002/9781119815631.ch23

Cited by 14 publications

(12 citation statements)

References 126 publications

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“…The DMSP spacecraft have sun-synchronous orbits near an altitude of 850 km. SSUSI measured auroral luminosity in a swath either side of the spacecraft orbit in the Lyman-Birge-Hopfield short (LBHs) band, 140-150 nm (see Paxton and Zhang, 2016;Paxton et al, 2017Paxton et al, , 2021 and the references cited therein for further description of the instrument and data products). Measurements of the distribution of magnetosphere-ionosphere field aligned currents (FACs) were provided by the Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE) technique (Anderson et al, 2000;Coxon et al, 2018;Waters et al, 2001).…”

Section: Observationsmentioning

confidence: 99%

The Association of Cusp‐Aligned Arcs With Plasma in the Magnetotail Implies a Closed Magnetosphere

et al. 2023

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We investigate a 15‐day period in October 2011. Auroral observations by the Special Sensor Ultraviolet Spectrographic Imager instrument onboard the Defense Meteorological Satellite Program F16, F17, and F18 spacecraft indicate that the polar regions were covered by weak cusp‐aligned arc (CAA) emissions whenever the interplanetary magnetic field (IMF) clock angle was small, |θ| < 45°, which amounted to 30% of the time. Simultaneous observations of ions and electrons in the tail by the Cluster C4 and Geotail spacecraft showed that during these intervals dense (≈1 cm−3) plasma was observed, even as far from the equatorial plane of the tail as |ZGSE| ≈ 13 RE. The ions had a pitch angle distribution peaking parallel and antiparallel to the magnetic field and the electrons had pitch angles that peaked perpendicular to the field. We interpret the counter‐streaming ions and double loss‐cone electrons as evidence that the plasma was trapped on closed field lines, and acted as a source for the CAA emission across the polar regions. This suggests that the magnetosphere was almost entirely closed during these periods. We further argue that the closure occurred as a consequence of dual‐lobe reconnection. Our finding forces a significant re‐evaluation of the magnetic topology of the magnetosphere during periods of northwards IMF.

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Section: Observationsmentioning

confidence: 99%

The Association of Cusp‐Aligned Arcs With Plasma in the Magnetotail Implies a Closed Magnetosphere

et al. 2023

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“…The orbital inclination is 74° and the altitude is 630 km. GUVI, one of the four instruments on TIMED, obtains the FUV spectrum (Christensen et al, 2003;Paxton et al, 2004Paxton et al, , 2017Paxton et al, , 2021. In an "imaging mode", GUVI provides imaging data at five FUV wavelength intervals or colors (121.6, 130.4, 135.6, 140-150, and 165-180 nm).…”

Section: Data Descriptionmentioning

confidence: 99%

Simultaneous Detection of Signatures of Conjugate Photoelectrons in the Ionosphere and Thermosphere

2022

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We investigate the impact of conjugate photoelectrons (CPEs) on the topside (∼600 km altitude) ionosphere at low and midlatitudes using measurements of the ion temperature, density, and composition from the first Republic of China satellite during a period of the high to moderate solar activity (March 1999 to June 2004). Elevated ion temperatures and densities are observed in the dark Northern American‐Atlantic sector during the December solstice and in the Australian sector during the June solstice. The oxygen ion fraction and density are also elevated at these locations. These observations indicate that photoelectrons from the conjugate hemisphere heat the local ionospheric plasma. The morphology of the ion temperature in the winter hemisphere is well represented by the solar zenith angle in the sunlit conjugate hemisphere. The CPE hypothesis for the observed ionospheric heating is confirmed by coincident nighttime enhancements of the far ultraviolet airglow measured by the Global Ultraviolet Imager onboard the Thermosphere Ionosphere Mesosphere Energetics and Dynamics satellite.

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“…Similarly, reduction in O/N 2 ratio and electron density is also expected due to the dissipation of gravity waves (Jones et al, 2020) and planetary waves (Yue & Wang, 2014). We use observations of column O/N 2 ratio (ΣO N / ) 2 by the Global Ultraviolet Imager (GUVI) onboard the Thermosphere, Ionosphere, Mesosphere Energetics, and Dynamics (TIMED) satellite (Meier, 2021;Paxton et al, 2017Paxton et al, , 2021Strickland et al, 1995; to examine whether anomalous ΣO N / 2 variations can be attributed to the SSW of September 2019. Background thermospheric ΣO N / 2 is calculated as a median value of all observations collected from 2008 to 2018, 2020 for low solar flux conditions (F10.7 < 80), low geomagnetic activity (Ap for the current day and previous day < 13), and centered on September 15 ± 10 days.…”

Section: Thermospheric Anomaliesmentioning

confidence: 99%

Impact of September 2019 Antarctic Sudden Stratospheric Warming on Mid‐Latitude Ionosphere and Thermosphere Over North America and Europe

Гончаренко

Harvey

Greer

et al. 2021

Geophysical Research Letters

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Significant progress in understanding mechanisms connecting the lower and upper atmosphere was achieved within the last decade by focusing on the analysis of sudden stratospheric warming events (SSWs). SSWs are large-scale phenomena characterized by rapid temperature increases in the winter high-latitude stratosphere, disruptions to the polar vortex, and decelerations or reversals of the stratospheric zonal winds. A review by Baldwin et al. (2021) summarizes the current state of knowledge about the mechanisms driving SSWs. Dramatic anomalies associated with SSWs are not limited to the stratosphere and have large impacts from the ocean to the ionosphere (see Pedatella et al., 2018 and references therein). Downward propagation of stratospheric disturbances affects tropospheric weather and leads to anomalous cold air outbreaks over Europe, Asia, and the eastern U.S.

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Exploring the Upper Atmosphere

Cited by 14 publications

References 126 publications

The Association of Cusp‐Aligned Arcs With Plasma in the Magnetotail Implies a Closed Magnetosphere

The Association of Cusp‐Aligned Arcs With Plasma in the Magnetotail Implies a Closed Magnetosphere

Simultaneous Detection of Signatures of Conjugate Photoelectrons in the Ionosphere and Thermosphere

Impact of September 2019 Antarctic Sudden Stratospheric Warming on Mid‐Latitude Ionosphere and Thermosphere Over North America and Europe

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