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Communication Dans Un Congrès Année : 2020

Modeling of SEP induced auroral emission at Mars: Proton contribution to the low altitude peak and effects of crustal fields

Résumé

Since Mars lacks a global intrinsic magnetic field, Solar Energetic Particles (SEPs) can directly precipitate into its atmosphere, causing increased ionization, dissociation and excitation of the atmospheric molecules. Simultaneous observations with Solar Energetic Particle (SEP) and the Imaging UltraViolet Spectrograph (IUVS) instruments on board the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft have revealed the existence of SEP induced diffuse auroral emission spanning across nightside Mars [Schneider et al., 2015, 2018]. Several model studies showed that about 100 keV monoenergetic electron precipitation should have been at the origin of the low altitude (~60 km) peak of the limb emission of CO2+ ultraviolet doublet [Schneider et al., 2015; Gérard et al., 2017; Haider et al., 2019]. However, no models were able to reproduce the low altitude emission peak using the observed electron energy population ranging from few keV to 200 keV. Previous auroral emission models did not take into account the contribution of MeV proton precipitation, although few MeV proton can penetrate down to ~60 km altitude as well [e.g., Jolitz et al., 2017]. This study aims to model the SEP induced diffuse auroral emission by both electrons and protons. In order to constrain the possible sources of the diffuse auroral emission, we focus on the different behaviors of the precipitating electrons and protons in the presence of crustal magnetic fields. In order to take into account the effects of crustal fields on the transport of electrons and protons, we have developed a Monte-Carlo collision and transport model of SEP electrons and protons with magnetic fields on Mars. The altitude profiles of the auroral emission by both electrons and protons will be presented.
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Dates et versions

insu-04463658 , version 1 (17-02-2024)

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Citer

Y. Nakamura, N. Terada, H. Nakagawa, S. Sakai, S. Hiruba, et al.. Modeling of SEP induced auroral emission at Mars: Proton contribution to the low altitude peak and effects of crustal fields. American Geophysical Union, Fall Meeting 2020, Dec 2020, Online, Unknown Region. pp.abstract #P047-0007. ⟨insu-04463658⟩
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