HR: 14:40h
AN: SH53C-04    [Abstracts]
TI: Effects of Solar Energetic Particle Events on the Martian Surface and Atmosphere
AU: Leblanc, F
EM: francois.leblanc@aerov.jussieu.fr
AF: Service d'A‚ronomie du CNRS, Service d'a‚ronomie Route des Gatines 91371 VerriŠres le Buisson C‚dex, VerriŠres le Buisson, 91371 C‚de France
AU: * Brain, D A
EM: brain@ssl.berkeley.edu
AF: UC Berkeley Space Sciences Lab, Space Sciences Lab University of California 7 Gauss Way, Berkeley, CA 94720 United States
AU: Luhmann, J G
EM: jgluhmann@ssl.berkeley.edu
AF: UC Berkeley Space Sciences Lab, Space Sciences Lab University of California 7 Gauss Way, Berkeley, CA 94720 United States
AU: Delory, G T
EM: gdelory@ssl.berkeley.edu
AF: UC Berkeley Space Sciences Lab, Space Sciences Lab University of California 7 Gauss Way, Berkeley, CA 94720 United States
AU: Mewaldt, R A
AF: SRL / Caltech, Caltech 220-47 Downs, Pasadena, CA 91125 United States
AU: Cohen, C M
AF: SRL / Caltech, Caltech 220-47 Downs, Pasadena, CA 91125 United States
AB: Characterization of the Martian radiation environment is a major objective identified by MEPAG in preparation for human exploration of Mars, and includes both determination of the ionizing radiation environment at the surface, and the shielding properties of the Martian atmosphere. Solar energetic charged particles (SEPs) provide an important component of ionizing radiation at Mars, especially during periods of high solar activity. Further, SEP events affect the Martian atmosphere at all altitudes, contributing to increased levels of atmospheric heating and loss. In this work we trace trajectories of test particles subject to interaction with Mars' neutral atmosphere and crustal magnetic fields. We show the penetration depth through the Martian atmosphere as a function of energy and incidence angle for energetic protons, and show that crustal magnetic fields affect SEP energy deposition in the atmosphere. We will provide estimates of the primary proton surface flux and energy deposition for a single large SEP event, such as the one observed in late October of 2003, showing that SEP surface effects exceed those from galactic cosmic rays by an order of magnitude or more during this event. Finally, we will discuss intriguing observations by the electron reflectometer (ER) on the Mars Global Surveyor Spacecraft (MGS) that show a geographic dependence of high energy particles observed during SEP events.
DE: 5421 Interactions with particles and fields
DE: 6225 Mars
DE: 2118 Energetic particles, solar
SC: SPA-Solar and Heliospheric Physics [SH]
MN: 2004 AGU Fall Meeting