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

Abstract

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.

Comprehensive calculation of the energy per ion pair or <I>W</I> values for five major planetary upper atmospheres

“…We use the TRANS-* family of codes adapted to Earth , Venus (Gronoff et al, , 2008, Mars (Simon et al, 2009), Titan (Lilensten et al, 2005;) and Jupiter (Ménager et al, 2010) as discussed below. The TRANS-* codes solve the 1-D kinetic transport Boltzmann equation for suprathermal electrons including updated elastic, ionisation, excitation and dissociative cross sections.…”

Auroral Processes at the Giant Planets: Energy Deposition, Emission Mechanisms, Morphology and Spectra

“…Fig. 3 Comparison of the profile in altitude of the electron production rate at Jupiter between the models of Grodent et al (2001) [Gr01], Hiraki and Tao (2008) [HT08], Menager et al (2010) [Me10] and Galand et al (2011) [Ga11]. The incident electron energy distribution is a triple Maxwellian applied to discrete aurora as defined by Grodent et al (2001).…”

Sensitivity of upper atmospheric emissions calculations to solar/stellar UV flux

“…For most of the simulations a double Gaussian intensity is used as in Menager et al (2010). If we consider that the upper atmospheric temperature is much lower than the emission temperature of the stellar line (around 30,000 K for the center of the line and between 4000 and 7000 K for the line wings; Vernazza et al 1981), only the center of the line is scattered by the planetary atmosphere.…”

“…We used the radiative transfer code mentioned in Barthélemy et al (2005) and Menager et al (2010). In these studies, the Lyman a line is used as a diagnostic tool for the upper atmospheres.…”

“…These diagnostics can be made through models such as the TRANS* family models, developed to study planetary ionospheres such as Earth (Lilensten & Blelly 2002), Mars (Witasse et al 2002(Witasse et al , 2003Simon et al 2009), Venus (Gronoff et al 2008), Titan (Lilensten et al 2005a(Lilensten et al , 2005bGronoff et al 2009aGronoff et al , 2009b, and Jupiter (Menager et al 2010). The TRANS* family models are 1D kinetic models which solve the Boltzmann equation for the suprathermal electrons along a vertical (or a magnetic field line) in the atmosphere.…”