The Charged Particle Environment on the Surface of Mars induced by Solar Energetic Particles - Five Years of Measurements with the MSL/RAD instrument
Abstract
NASA's Mars Science Laboratory (MSL) mission has now been operating in Gale crater on the surface of Mars for five years. On board MSL, the Radiation Assessment Detector (MSL/RAD) is measuring the Martian surface radiation environment, providing insights on its intensity and composition. This radiation field is mainly composed of primary Galactic Cosmic Rays (GCRs) and secondary particles created by the GCRs' interactions with the Martian atmosphere and soil. However, on shorter time scales the radiation environment can be dominated by contributions from Solar Energetic Particle (SEP) events. Due to the modulating effect of the Martian atmosphere shape and intensity of these SEP spectra will differ significantly between interplanetary space and the Martian surface. Understanding how SEP events influence the surface radiation field is crucial to assess associated health risks for potential human missions to Mars. Here, we present updated MSL/RAD results for charged particle fluxes measured on the surface during SEP activity from the five years of MSL operations on Mars. The presented results incorporate updated analysis techniques for the MSL/RAD data and yield the most robust particle spectra to date. Furthermore, we compare the MSL/RAD SEP-induced fluxes to measurements from other spacecraft in the inner heliosphere and, in particular, in Martian orbit. Analyzing changes of SEP intensities from interplanetary space to the Martian surface gives insight into the modulating effect of the Martian atmosphere, while comparing timing profiles of SEP events between Mars and different points in interplanetary space can increase our understanding of SEP propagation in the heliosphere.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2017
- Bibcode:
- 2017AGUFMSH34B..08E
- Keywords:
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- 2134 Interplanetary magnetic fields;
- INTERPLANETARY PHYSICS;
- 7514 Energetic particles;
- SOLAR PHYSICS;
- ASTROPHYSICS;
- AND ASTRONOMY;
- 7959 Models;
- SPACE WEATHER;
- 7984 Space radiation environment;
- SPACE WEATHER