Modeling of diffuse aurora in the Nighttime Atmosphere of Mars: Simulations and Observation
Abstract
Aurorae are observed on various solar system bodies. It helps us to understand the complex relationship between an atmosphere and solar wind plasma around it. Martian Aurorae has come to known since 2004 with the help of observations from ultraviolet spectrometers. In the Martian atmosphere, Carbon dioxide is a major species, gets ionized by various mechanism. These incorporates direct processes such as ionization by solar photon, galactic cosmic rays and solar wind electron. During nighttime, excess energy deposited by the energetic electrons into the atmosphere ionizes carbon dioxide. This leads to the formation of auroral emission and produces CO$ _{2}$$ ^{+}$ Ultraviolet Doublet (UVD) emission in the ultraviolet. During December 2014, the Mars Atmosphere and Volatile Evolution (MAVEN) recorded significant enhancement in the energetic electron fluxes. The data from Solar Energetic Particle Package and Imaging Ultraviolet Spectrograph (IUVS) has been utilized in the study. We present the modelling of CO$_{2}$pUVD to look into the significant reduction in the ionization peak altitude due to the electron impact ionization. The modelling has been carried out using hybrid model and four dimensional yield spectrum approach based on Monte Carlo simulation. We have calculated the ionization rates, ion and electron densities and limb intensity of diffuse aurora due to precipitation of solar energetic particle and proton hydrogen (H$^{+}$-H) fluxes in the nighttime ionosphere of Mars. The modelled limb intensities due to impact of H$^{+}$-H and SEP electrons are compared with the IUVS observations of CO$_{2}$pUVD emission during 17-21 December 2014.
- Publication:
-
43rd COSPAR Scientific Assembly. Held 28 January - 4 February
- Pub Date:
- January 2021
- Bibcode:
- 2021cosp...43E.757J