Electron transport and energy degradation in the ionosphere: evaluation of the numerical solution, comparison with laboratory experiments and auroral observations

Lummerzheim, D.; Lilensten, J.

doi:10.1007/s005850050127

Cited by 72 publications

(91 citation statements)

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“…It has been adapted to several planets, becoming successively transsolo (Lummerzheim & Lilensten 1994), transcar (Lilensten & Blelly 2002), tran4 ) in the case of Earth, and, for orther planets, transTitan (Lilensten et al 2005a,b), transMars (Witasse et al 2003(Witasse et al , 2002Simon et al 2008), transVenus (Gronoff et al 2007. The transTitan code used here consists of primary production through photoabsorption and secondary production through electron impacts.…”

Section: The Transtitan Modelmentioning

confidence: 99%

Ionization processes in the atmosphere of Titan

Gronoff¹,

Lilensten²,

Desorgher

et al. 2009

A&A

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Context. The Cassini probe regularly passes in the vicinity of Titan, revealing new insights into particle precipitation thanks to the electron and proton spectrometer. Moreover, the Huygens probe has revealed an ionized layer at 65 km induced by cosmic rays. The impact of these different particles on the chemistry of Titan is probably very strong. Aims. In this article, we compute the whole ionization in the atmosphere of Titan: from the cosmic rays near the ground to the EUV in the upper atmosphere. The meteoritic layer is not taken into account. Methods. We used the transTitan model to compute the electron and EUV impact, and the planetocosmics code to compute the influence of protons and oxygen ions. We coupled the two models to study the influence of the secondary electrons obtained by planetocosmics through the transTitan code. The resulting model improves the accuracy of the calculation through the transport of electrons in the atmosphere. Results. The whole ionization is computed and studied in details. During the day, the cosmic ray ionization peak is as strong as the UV-EUV one. Electrons and protons are very important depending the precipitation conditions. Protons can create a layer at 500 km, while electrons tend to ionize near 800 km. The oxygen ion impact is near 900 km. The results shows few differences to precedent models for the nightside T5 fly-by of Cassini, and can highlight the sources of the different ion layers detected by radio measurements. Conclusions. The new model successfully computes the ion production in the atmosphere of Titan. For the first time, a full electron and ion profile has been computed from 0 to 1600 km, which compares qualitatively with measurements. This result can be used by chemical models.

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Section: The Transtitan Modelmentioning

confidence: 99%

Ionization processes in the atmosphere of Titan

Gronoff¹,

Lilensten²,

Desorgher

et al. 2009

A&A

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“…Lummerzheim et al (1989) solved the electron transport equation by separating the energy degradation from the transport and scattering equation, and used a discrete ordinate method. This last approach has been discussed in Lummerzheim and Lilensten (1994), and validated through comparisons with laboratory experiments and auroral observations. Later, it has been widely used, for example to understand the physics of arcs (Lanchester et al, 1994) and, combined with a chemistry and dynamics code, to describe the high latitude conductances or the e ect of substorms on ion composition Lathuillere et al, 1997).…”

Section: Introductionmentioning

confidence: 99%

Proton-electron precipitation effects on the electron production and density above EISCAT (Tromsø) and ESR

Lilensten¹,

Galand

1998

Ann Geophysicae

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Abstract. The suprathermal particles, electrons and protons, coming from the Sun and precipitating into the high-latitude atmosphere are an energy source for the Earth's ionosphere. They interact with the ambient thermal gas through inelastic and elastic collisions. Most of the physical quantities perturbed by the precipitation, such as the electron production rate, may be evaluated by solving the stationary Boltzmann transport equation, which yields the particle¯uxes as a function of altitude, energy, and pitch angle. This equation has been solved for the three di erent suprathermal species (electrons, protons and hydrogen atoms). We ®rst compare the results of our theoretical code to a coordinated DMSP/EISCAT experiment, and to another approach. Then, we show the e ects that pure proton precipitation may have on the ionosphere, through primary and secondary ionization. Finally, we compare the e ects of proton precipitation and electron precipitation in some selected cases above EISCAT (Tromsù) and ESR.

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“…However, first principle auroral models can also provide spectral simulations of complete volume emission profiles for a given differential incident energy spectrum and thermospheric conditions [Lummerzheim et al, 1994]. The modeled peak emission altitude and profile shape have been shown to be sensitive to the incident energetics.…”

Section: Comparison Of Vertical Profilesmentioning

confidence: 99%