Analysis of electron impact ionization properties of methane

Liu, Xianming; Shemansky, D. E.

doi:10.1029/2005ja011454

Cited by 43 publications

(35 citation statements)

References 116 publications

(347 reference statements)

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“…Given the lack of data concerning the Liu & Shemansky (2006) phase function which describes the elastic scattering of electrons by the hydrogen molecule, the elastic scattering of low energy electrons is described by the phase function given by Porter et al (1987). This function is accurate for scattering by nitrogen but tests with other phase functions showed that it does not change the results of more than 3%.…”

Section: Auroral Electron Precipitation 231 Collisions Between Thementioning

confidence: 99%

H Lymanαline in Jovian aurorae: electron transport and radiative transfer coupled modelling

Menager¹,

Barthélemy²,

Lilensten³

2010

A&A

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Aims. The aim of this work is to characterize the impact of the solar UV flux and of the electron precipitation on Jupiter's atmosphere and to study the H Lyman α intensity and spectral profile in Jupiter's aurorae. In particular we characterize the sensitivity of the line to the relevant input parameters. Methods. We use a multi-stream electron transport code solving the 1D Boltzmann equation and a Feautrier technique radiative transfer code. Results. We calculate ionization rate profiles of the main species of Jupiter's ionosphere and the heating rate due to electron precipitation, as a function of the energy of the precipitation. We also calculate the emission rate of Lyman α photons under auroral electron precipitation and the ensuing line profile. The profile exhibits a centre reversal which could be used as a diagnostic of Jupiter's auroral low-energy electron precipitation.

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Section: Auroral Electron Precipitation 231 Collisions Between Thementioning

confidence: 99%

H Lymanαline in Jovian aurorae: electron transport and radiative transfer coupled modelling

Menager¹,

Barthélemy²,

Lilensten³

2010

A&A

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“…where the integral extends from the ionization threshold of neutral species m to 28 keV, which is the upper limit of the CAPS/ELS energy range, n m is the number density of molecular species m (N 2 or CH 4 ) (derived from INMS/CSN, see Cui et al, 2012) and σ m (E) is the total electron-impact ionization cross section of m at energy E. The cross sections for N 2 and CH 4 electron-impact ionization are taken from Itikawa (2006) and Liu and Shemansky (2006). To assess I e we have mainly made use of the CAPS/ELS anode 2 measurements taking the average over four 2s spectra recorded near the altitude of interest.…”

Section: Electron Production Ratementioning

confidence: 99%

Ionization balance in Titan’s nightside ionosphere

Vigren

Galand

Yelle

et al. 2015

Icarus

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Ionization balance in Titan's nightside ionosphere, Icarus (2014), doi: http://dx.doi.org/10.1016/j.icarus. 2014.11.012 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. ABSTRACTBased on a multi-instrumental Cassini dataset we make model versus observation comparisons of plasma number densities, n P =(n e n I ) 1/2 (n e and n I being the electron number density and total positive ion number density, respectively) and short-lived ion number densities (N + , CH 2 + , CH 3 + , CH 4 + ) in the southern hemisphere of Titan's nightside ionosphere over altitudes ranging from 1100 and 1200 km and from 1100 to 1350 km, respectively. The n P model assumes photochemical equilibrium, ionelectron pair production driven by magnetospheric electron precipitation and dissociative recombination as the principal plasma neutralization process. The model to derive short-lived-ion number densities assumes photochemical equilibrium for the short-lived ions, primary ion production by electron-impact ionization of N 2 and CH 4 and removal of the short-lived ions through reactions with CH 4 . It is shown that the models reasonably reproduce the observations, both with regards to n P and the number densities of the short-lived ions. This is contrasted by the difficulties in accurately reproducing ion and electron number densities in Titan's sunlit ionosphere.

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“…Thanks to recent laboratory measurements or theoretical derivations, more accurate cross section sets, such as electron impact ionization cross sections of N 2 (Shemansky and Liu 2005) and CH 4 (Liu and Shemansky 2006), excitation cross sections associated with N 2 LBH band emissions , excitation cross sections of O 2 (Kanik et al 2003;Jones et al 2006) and proton charge-transfer cross section with O (Pandey et al 2007), are now available. They will help towards more reliable auroral transport modelling results at planets and moons in the Solar System, with possible implication on auroral diagnostic (e.g., ).…”

Section: Auroramentioning

confidence: 98%