Investigating Solar Flare-Induced Oxygen Production in the Martian Thermosphere
Abstract
In-situ observations of the upper atmosphere of Mars demonstrate that the densities of neutral species increase in the thermosphere following the arrival of solar flare irradiance. An examination of these structural and compositional changes is important for understanding the evolution and escape of the early atmosphere of Mars, as flares in the early solar system occurred with much greater frequency. The X8.2-class solar flare on September 10, 2017 is an excellent source for investigating these atmospheric changes due to its large magnitude and the orbital geometry of the Mars Atmosphere and Volatile EvolutioN (MAVEN) spacecraft, which resulted in observations of significant atmospheric effects at Mars less than two hours after the flare. By piecing apart the roles of thermal expansion and chemical processes in producing the density and compositional changes recorded by MAVEN NGIMS during this event, we find that chemical processes cause the O/CO2 ratio to more than double in the hours following the flare before returning to previous levels. As the dominant species at altitudes above approximately 210 km, neutral atomic oxygen is especially significant in characterizing comprehensive upper atmospheric changes, and is the subject of our upcoming work.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.P41B3445C
- Keywords:
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- 0343 Planetary atmospheres;
- ATMOSPHERIC COMPOSITION AND STRUCTURE;
- 6225 Mars;
- PLANETARY SCIENCES: SOLAR SYSTEM OBJECTS;
- 5405 Atmospheres;
- PLANETARY SCIENCES: SOLID SURFACE PLANETS;
- 5445 Meteorology;
- PLANETARY SCIENCES: SOLID SURFACE PLANETS