Angular distribution of electrons elastically scattered from ozone

Shyn, T. W.; Sweeney, Christopher J.

doi:10.1103/physreva.47.2919

Cited by 36 publications

(57 citation statements)

References 7 publications

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“…[21] After impact, the energy of the suprathermal electrons is transferred to methane molecules as kinetic energy (elastic collisions) and internal excitation (inelastic collisions), including vibrational excitation, rotational excitation, and electronic excitation. In the present study, the cross sections corresponding to these four processes are the same as those used in the model of [Gan, 1991;Jain and Thomson, 1983;Jain, 1986;Shyn and Cravens, 1990;Tanaka et al, 1983;Sohn et al, 1983;Shimamura, 1983;Muller et al, 1985;Brescansin et al, 1989]. They are plotted in Figure 3, where they are compared with the ionization cross sections of Orient and Srivastava [1987], used in the coupled ion and neutral model of De La Haye et al [2008].…”

Section: Excitation Of Methanementioning

confidence: 99%

Heating Titan's upper atmosphere

et al. 2008

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[1] A detailed analysis of the mechanisms heating Titan's neutral atmosphere is provided. Two primary sources of incoming energy, the solar photons and the energetic electrons from Saturn's magnetosphere, are taken into account. The processes studied include the excitation of atmospheric molecules by electron impact, suprathermal electron heating, and the energy release through ion and neutral exothermic chemistry. The redistribution of heat by suprathermal particles throughout the atmosphere is also considered and calculated using a two-stream model. Local time-dependent heating rate profiles are presented. Exothermic chemistry is found to be the dominant source of heat, with electron-impact excitation and suprathermal electron heating becoming significant at high altitudes. Large variations in local peak amplitudes were found, varying between '3 Â 10 À10 erg cm À3 s À1 at 990 km and zenith angle 62°and '7 Â 10 À12 erg cm À3 s À1 at 940 km and zenith angle 165°. Neutral heating efficiency profiles averaged with respect to local time at the fixed latitudes of 38.8°N and 73.7°N are presented, with mean values of '25 ± 15% and 23 ± 19%, respectively.

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Section: Excitation Of Methanementioning

confidence: 99%

Heating Titan's upper atmosphere

et al. 2008

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“…The presence of the stable ozonide anion, O − 3 , is well known and there have been several recent investigations, both theoretical (Borowski et al 1995) and experimental (Arnold et al 1994), attempting to characterize its spectroscopic properties. The interaction of lowenergy electrons with ozone has also received considerable attention recently (Davies et al 1993, Shyn and Sweeney 1993, Sweeney and Shyn 1996, Allan et al 1996, Walker et al 1996, Skalny et al 1996 with both vibrationally inelastic and dissociative attachment cross sections being measured. Both of these processes, which are important for the study of ozone chemistry in the upper atmosphere, are driven primarily by resonance states of the negatively charged complex.…”

Section: Introductionmentioning

confidence: 99%

Calculated integral and differential cross sections for electron scattering by ozone

Sarpal

Nestmann²,

Peyerimhoff³

1998

J. Phys. B: At. Mol. Opt. Phys.

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Elastic scattering of electrons by ozone is considered. Calculations, using the polyatomic R-matrix method, at the static exchange level and those including polarization effects are reported. Differential and integral cross sections are presented and found to be in good agreement with experiment. Our calculations are shown to be consistent with the recent measurement of the dissociative attachment cross section.

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“…The assumption of photochemical equilibrium, which we show below is not appropriate, accounts for about $km of the difference for the magnetotail spectrum. Most of the difference, however, arises from our use of a high solar activity model rather than the moderate solar activity model employed by lIaider eta!., and from the use of the CO• elastic cross sections ofShyn et al [1978], rather than those…”

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confidence: 99%

Upper limits to the nightside ionosphere of Mars

Fox

Brannon

Porter

1993

Geophysical Research Letters

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The nightside ionosphere of Mars could be produced by electron precipitation or by plasma transport from the dayside, by analogy to the Venus, but few measurements are available. We report here model calculations of upper limits to the nightside ion densities on Mars that would be produced by both mechanisms. For the auroral model, we have adopted the downward traveling portions of the electron spectra measured by the HARP instrument on the Soviet Phobos spacecraft in the Martian plasma sheet and in the magnetotail lobes. For the plasma transport case, we have imposed on a model of the nightside thermosphere, downward fluxes of O+, C+, N+, NO+ and O+2 that are near the maximum upward fluxes that can be sustained by the dayside ionosphere. The computed electron density peaks are in the range (1.3–1.9) × 104 cm−3 at altitudes of 159 to 179 km. The major ion for all the models is O+2, but significant differences in the composition of the minor ions are found for the ionospheres produced by auroral precipitation and by plasma transport. The calculations reported here provide a guide to the data that should be acquired during a future aeronomy mission to Mars, in order to determine the sources of the nightside ionosphere.

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Angular distribution of electrons elastically scattered from ozone

Cited by 36 publications

References 7 publications

Heating Titan's upper atmosphere

Heating Titan's upper atmosphere

Calculated integral and differential cross sections for electron scattering by ozone

Upper limits to the nightside ionosphere of Mars

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