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A Monte Carlo model of crustal field influences on solar energetic particle precipitation into the Martian atmosphere
Author(s) -
Jolitz R. D.,
Dong C. F.,
Lee C. O.,
Lillis R. J.,
Brain D. A.,
Curry S. M.,
Bougher S.,
Parkinson C. D.,
Jakosky B. M.
Publication year - 2017
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1002/2016ja023781
Subject(s) - physics , ionization , martian , atmosphere (unit) , charged particle , snow , computational physics , mars exploration program , venus , solar energetic particles , atmosphere of mars , geophysics , astrobiology , nuclear physics , ion , coronal mass ejection , solar wind , plasma , meteorology , quantum mechanics
Solar energetic particles (SEPs) can precipitate directly into the atmospheres of weakly magnetized planets, causing increased ionization, heating, and altered neutral chemistry. However, strong localized crustal magnetism at Mars can deflect energetic charged particles and reduce precipitation. In order to quantify these effects, we have developed a model of proton transport and energy deposition in spatially varying magnetic fields, called Atmospheric Scattering of Protons and Energetic Neutrals. We benchmark the model's particle tracing algorithm, collisional physics, and heating rates, comparing against previously published work in the latter two cases. We find that energetic nonrelativistic protons precipitating in proximity to a crustal field anomaly will primarily deposit energy at either their stopping altitude or magnetic reflection altitude. We compared atmospheric ionization in the presence and absence of crustal magnetic fields at 50°S and 182°E during the peak flux of the 29 October 2003 “Halloween storm” SEP event. The presence of crustal magnetic fields reduced total ionization by ~30% but caused ionization to occur over a wider geographic area.