Thermospheric distribution of fast O(1D) atoms

Kharchenko, V.; Dalgarno, A.; Fox, Jane L.

doi:10.1029/2005ja011232

Cited by 17 publications

(14 citation statements)

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“…Observational evidence of this nonthermal population utilizes various techniques: twilight observations of the 732.0 and 733.0 nm airglow emission from the ground [ Yee et al , ], redline intensity measurements made by the Visible Airglow Experiment on the Atmosphere Explorer‐C satellite [ Schmitt et al , ], red line temperature measurements from the FPI on the Dynamics Explorer satellite [ Hubert et al , ], and in situ measurements made by the low energy neutral atom (LENA) instrument on the IMAGE spacecraft [ Wilson and Moore , ]. This evidence is supported by modeling which suggests that a nonthermal population is present above 200 km, which should increase FPI red line temperature measurements above the ambient temperature [ Shematovich et al , ; Sipler and Biondi , ; Kharchenko et al , ]. In this paper, we present observational evidence that nonthermal oxygen atoms affect the wind measurement as well as the temperature, at least during geomagnetically active periods.…”

Section: Discussionmentioning

confidence: 99%

Storm time response of the midlatitude thermosphere: Observations from a network of Fabry‐Perot interferometers

et al. 2014

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Observations of thermospheric neutral winds and temperatures obtained during a geomagnetic storm on 2 October 2013 from a network of six Fabry‐Perot interferometers (FPIs) deployed in the Midwest United States are presented. Coincident with the commencement of the storm, the apparent horizontal wind is observed to surge westward and southward (toward the equator). Simultaneous to this surge in the apparent horizontal winds, an apparent downward wind of approximately 100 m/s lasting for 6 h is observed. The apparent neutral temperature is observed to increase by approximately 400 K over all of the sites. Observations from an all‐sky imaging system operated at the Millstone Hill observatory indicate the presence of a stable auroral red (SAR) arc and diffuse red aurora during this time. We suggest that the large sustained apparent downward winds arise from contamination of the spectral profile of the nominal thermospheric 630.0 nm emission by 630.0 nm emission from a different (nonthermospheric) source. Modeling demonstrates that the effect of an additional population of 630.0 nm photons, with a distinct velocity and temperature distribution, introduces an apparent Doppler shift when the combined emissions from the two sources are analyzed as a single population. Thus, the apparent Doppler shifts should not be interpreted as the bulk motion of the thermosphere, calling into question results from previous FPI studies of midlatitude storm time thermospheric winds. One possible source of contamination could be fast O related to the infusion of low‐energy O+ ions from the magnetosphere. The presence of low‐energy O+ is supported by observations made by the Helium, Oxygen, Proton, and Electron spectrometer instruments on the twin Van Allen Probes spacecraft, which show an influx of low‐energy ions during this period. These results emphasize the importance of distributed networks of instruments in understanding the complex dynamics that occur in the upper atmosphere during disturbed conditions.

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Section: Discussionmentioning

confidence: 99%

Storm time response of the midlatitude thermosphere: Observations from a network of Fabry‐Perot interferometers

et al. 2014

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“…As Kharchenko et al (2005) show, the hot oxygen fraction at these heights is ∼ 5 % during daytime. Even though most of the overlapping profiles used in this work fall in 18-6 h local time interval, the MLT area is illuminated by the sun in at least half of the selected events (the shadow level at 100 km corresponds to solar zenith angle θ z = 101 • , and the average θ z is 105 ± 30 • ).…”

Section: Discussionmentioning

confidence: 80%

“…(2) and (3) in the non-LTE models. However, as Balakrishnan et al (1998) and Kharchenko et al (2005) show, the non-thermal O ( O + 2 dissociative recombination reactions in the MLT. These "hot" atoms may serve as an additional source of CO 2 (ν 2 ) level excitation.…”

Section: Discussionmentioning

confidence: 99%

CO2(ν2)-O quenching rate coefficient derived from coincidental SABER/TIMED and Fort Collins lidar observations of the mesosphere and lower thermosphere

et al. 2012

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Abstract. Among the processes governing the energy balance in the mesosphere and lower thermosphere (MLT), the quenching of CO 2 (ν 2 ) vibrational levels by collisions with O atoms plays an important role. However, there is a factor of 3-4 discrepancy between the laboratory measurements of the CO 2 -O quenching rate coefficient, k VT , and its value estimated from the atmospheric observations. In this study, we retrieve k VT in the altitude region 85-105 km from the coincident SABER/TIMED and Fort Collins sodium lidar observations by minimizing the difference between measured and simulated broadband limb 15 µm radiation. The averaged k VT value obtained in this work is 6.5 ± 1.5 × 10 −12 cm 3 s −1 that is close to other estimates of this coefficient from the atmospheric observations. However, the retrieved k VT also shows altitude dependence and varies from 5.5 ± 1.1 × 10 −12 cm 3 s −1 at 90 km to 7.9 ± 1.2 × 10 −12 cm 3 s −1 at 105 km. Obtained results demonstrate the deficiency in current non-LTE modeling of the atmospheric 15 µm radiation, based on the application of the CO 2 -O quenching and excitation rates, which are linked by the detailed balance relation. We discuss the possible model improvements, among them accounting for the interaction of the "non-thermal" oxygen atoms with CO 2 molecules.

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“…Evolution of the system with the effective diffusion coefficient (12) was described in Ref. [22]. It was shown that such complex systems manifest an anomalous diffusion.…”

Section: Modelmentioning

confidence: 99%

Entropy-driven phase transitions with influence of the field-dependent diffusion coefficient

Kharchenko

2009

Physica A: Statistical Mechanics and its Applications

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We present a comprehensive study of the phase transitions in the single-field reaction-diffusion stochastic systems with field-dependent mobility of a power-low form and the internal fluctuations. Using variational principles and mean-field theory it was shown that the noise can sustain spatial patterns and leads to disordering phase transitions. We have shown that the phase transitions can be of critical or non-critical character.

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Thermospheric distribution of fast O(¹D) atoms

Abstract: atoms. The nonthermal atoms comprise 4-6% of the distribution, and their effective temperatures are larger by 25-46% than the local temperatures of the ambient gas. The role of hot metastable oxygen atoms in the production of vibrationally excited OH molecules is analyzed.

Cited by 17 publications

References 80 publications

Storm time response of the midlatitude thermosphere: Observations from a network of Fabry‐Perot interferometers

Storm time response of the midlatitude thermosphere: Observations from a network of Fabry‐Perot interferometers

CO<sub>2</sub>(ν<sub>2</sub>)-O quenching rate coefficient derived from coincidental SABER/TIMED and Fort Collins lidar observations of the mesosphere and lower thermosphere

Entropy-driven phase transitions with influence of the field-dependent diffusion coefficient

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Thermospheric distribution of fast O(1D) atoms

Abstract: atoms. The nonthermal atoms comprise 4-6% of the distribution, and their effective temperatures are larger by 25-46% than the local temperatures of the ambient gas. The role of hot metastable oxygen atoms in the production of vibrationally excited OH molecules is analyzed.

Cited by 17 publications

References 80 publications

Storm time response of the midlatitude thermosphere: Observations from a network of Fabry‐Perot interferometers

Storm time response of the midlatitude thermosphere: Observations from a network of Fabry‐Perot interferometers

CO&lt;sub&gt;2&lt;/sub&gt;(ν&lt;sub&gt;2&lt;/sub&gt;)-O quenching rate coefficient derived from coincidental SABER/TIMED and Fort Collins lidar observations of the mesosphere and lower thermosphere

Entropy-driven phase transitions with influence of the field-dependent diffusion coefficient

Contact Info

Product

Resources

About

Thermospheric distribution of fast O(¹D) atoms

CO<sub>2</sub>(ν<sub>2</sub>)-O quenching rate coefficient derived from coincidental SABER/TIMED and Fort Collins lidar observations of the mesosphere and lower thermosphere