Non-thermal produced by dissociative recombination of O2+: A theoretical model and observational results

Schmitt, G. A.; Abreu, Vincent J.; Hays, P. B.

doi:10.1016/0032-0633(81)90008-8

Cited by 20 publications

(17 citation statements)

References 13 publications

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“…Such quiet time nonthermal oxygen atoms are thought to be produced mainly by dissociative recombination of O

_{2}^{+}

and NO + [ Hickey et al , ], as opposed to charge exchange with precipitating O + during active times, as discussed in the present paper. 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 , ].…”

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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“…Such quiet time nonthermal oxygen atoms are thought to be produced mainly by dissociative recombination of O

_{2}^{+}

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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“…Using a simple model, Schmitt et al (1981) have interpreted an excess of the 6300Å intensity above 600 km as evidence of nonthermal O( 1 D) atoms. In 1999, Shematovich et al have reported their studies of thermalization with a Monte Carlo model and predicted an excess O( 1 D) temperature of 350 K at noon for low solar activity conditions at the altitude of 300 km.…”

Section: Discussionmentioning

confidence: 99%

Doppler temperatures from O(<sup>1</sup>D) airglow in the daytime thermosphere as observed by the Wind Imaging Interferometer (WINDII) on the UARS satellite

et al. 2002

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Abstract. From 1992 to 1997, the WINDII interferometer on board the UARS satellite acquired a large set of thermospheric data from the O( 1 D) and O( 1 S) airglows. We report here for the first time on daytime O( 1 D) Doppler temperatures obtained with version 5.11 of the WINDII data processing software. Using a statistical analysis of the temperatures independently measured by the two WINDII fields of view, we estimate that the temperature variations larger than 40 K can be considered as geophysical. Comparisons of WINDII temperatures measured during magnetically quiet days with temperatures obtained by the MSIS-90 and DTM-94 thermospheric models show a 100 K bias. We demonstrate, however, that the modeled temperature variations represent very well the mean temperature variation observed by WINDII over 4 years. We also show that the observed latitudinal/local time variation is in very good agreement with the two empirical models. Finally, the temperature variations during a magnetically disturbed day are found to be qualitatively well represented in form by the models, but largely underestimated. The presence of non-thermal atoms and instrument related issues are discussed as possible explanations for the 100 K bias between the WINDII Doppler temperatures and the empirical models.

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“…These results, however, are weighted by the volume emission profile of the source emission along the line of sight, which is usually not known. The lifetime of the oxygen atom is sufficiently long for thermalization [Schmitt et al, 1981[Schmitt et al, , 1982, and the observed Doppler shift is taken to be representative of the general atmospheric motion.…”

Section: Measurements Of the Meridional Wind With The Fabry-perot Intmentioning

confidence: 99%

The meridional thermospheric neutral wind measured by radar and optical techniques in the auroral region

Wickwar¹,

Meriwether²,

Hays³

et al. 1984

J. Geophys. Res.

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Radar observations of ion velocities in the magnetic zenith over Chatanika, Alaska, were used to determine the geomagnetic meridional component of the thermospheric neutral wind. Corrections for molecular diffusion and molecular ion contamination of the pure O + composition assumed for the ionosphere were included in the analysis. Comparison of the averaged diurnal variation of the meridional wind showed good agreement between the two measurement techniques. Good agreement was also found for several cases of simultaneous observations. The evidence suggested that differences were caused by gravity waves. The 7 years of radar meridional wind results were examined with respect to magnetic activity, solar cycle phase, and season. During the day, the meridional component is poleward with a maximum of about 65 m/s between 1400 and 1600 local time. During the night, the wind is equatorward with a maximum of about 175 m/s between 0200 and 0500 local time. This maximum occurs after local magnetic midnight, which is about 0130 local time. When the neutral wind is averaged for 24 hours, there is a large net equatorward flow. During periods of increased magnetic activity, the nighttime wind between 2300 and 0600 local time becomes stronger toward the equator. The average increase between 0200 and 0600 local time is about 100 m/s; however, on individual days it can be as large as 400 m/s. These data pertain mostly to equinox, but the few summer and winter observations in the data set differ in the manner predicted by theory. Comparison of these results with theoretical models shows good agreement at most times, but suggests possible heating poleward of Chatanika during the morning hours. Observed exospheric temperature increases support this hypothesis. Hays et al., 1984] should result in further improvements of the thermospheric global circulation model (TGCM) formulation for the physics of high latitude dynamics.There remains, however, a dearth of ground-based measurements of geomagnetic meridional and zonal thermospheric winds with good temporal resolution at high latitudes. These measurements are an important part of the experimental tests required to examine the validity of the comprehensive threedimensional TGCM model results. These ground-based observations provide information on the diurnal variation of the F region neutral wind within the auroral convection zone. These observations greatly complement the global latitudinal sampling of thermospheric winds by the DE-B satellite.The geomagnetic meridional component of the thermospheric neutral wind may be calculated from Chatanika incoherent-scatter radar observations of field-aligned ion motions. Because the Chatanika radar could observe the magnetic zenith directly, the need to correct for horizontal transport caused by E x B drifts is avoided. Observations obtained during the 10 years that the radar was operational at Chatanika resulted in the formation of a data set that may be applied to study the behavior of the thermospheric neutral wind under varying conditions....

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Non-thermal produced by dissociative recombination of O2+: A theoretical model and observational results

Cited by 20 publications

References 13 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

Doppler temperatures from O(<sup>1</sup>D) airglow in the daytime thermosphere as observed by the Wind Imaging Interferometer (WINDII) on the UARS satellite

The meridional thermospheric neutral wind measured by radar and optical techniques in the auroral region

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Non-thermal produced by dissociative recombination of O2+: A theoretical model and observational results

Cited by 20 publications

References 13 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

Doppler temperatures from O(&lt;sup&gt;1&lt;/sup&gt;D) airglow in the daytime thermosphere as observed by the Wind Imaging Interferometer (WINDII) on the UARS satellite

The meridional thermospheric neutral wind measured by radar and optical techniques in the auroral region

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Doppler temperatures from O(<sup>1</sup>D) airglow in the daytime thermosphere as observed by the Wind Imaging Interferometer (WINDII) on the UARS satellite