Heidelberg 2022 – wissenschaftliches Programm

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EP: Fachverband Extraterrestrische Physik

EP 3: Planets and Small bodies

EP 3.2: Vortrag

Dienstag, 22. März 2022, 11:30–11:45, EP-H1

The impact of large solar particle events on the chemical composition of the Martian atmosphere — •Miriam Sinnhuber¹, John Lee Grenfell², Konstantin Herbst³, and Fabian Wunderlich² — ¹Karlsruher Institute für Technologie, Karlsruhe, Germany — ²DLR Institut für Planetenforschung, Berlin, Germany — ³Universität Kiel, Kiel, Germany

Large solar coronal mass ejections are known to have a large impact on the chemical composition of the high-latitude atmosphere of Earth. Collision of the incident protons and resulting secondary electrons with the most abundant atmospheric constituents leads to dissociation, ionization, and dissociative ionization of these substances; in the Earth’s atmosphere, these are N₂ and O₂, and the main products are nitrogen radicals and nitrogen oxides (NOx: N, NO, NO₂) as well as hydrogen oxides (HOx: OH, HO₂) from the uptake of water vapor into large cluster ions. Both NOx and HOx species contribute to catalytic ozone loss, and very rapid loss of ozone in the terrestrial polar stratosphere and mesosphere is well-documented. However, not much is known about the impact of these events on other planets. Here, we present results from model experiments for the atmosphere of Mars, considering three different solar particle events: a ground-level event (1956), the Carrington white light flare (1859), and one of the largest ground-level events found in the paleo-record so far, the AD774/775 event. The analysis focuses on the different responses of the thin Martian atmosphere with its low amounts of nitrogen and high CO₂ mixing ratio.