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Role of plasma waves in Mars' atmospheric loss
Author(s) -
Ergun R. E.,
Andersson L.,
Peterson W. K.,
Brain D.,
Delory G. T.,
Mitchell D. L.,
Lin R. P.,
Yau A. W.
Publication year - 2006
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2006gl025785
Subject(s) - mars exploration program , ionosphere , atmosphere of mars , solar wind , polar wind , physics , atmospheric sciences , plasma , geophysics , atmosphere (unit) , outflow , population , exosphere , astrobiology , ion , environmental science , magnetopause , meteorology , martian , demography , quantum mechanics , sociology
Recent observations of plasma waves, electron fluxes, and ion fluxes in Mars' ionosphere indicate that ion heating may have had a significant impact on Mars' atmospheric loss. We discuss two energy sources of plasma waves: the solar wind interaction with Mars and field‐aligned currents in regions of crustal magnetic fields. These plasma waves can damp through cyclotron resonance with the O + population in the ionosphere leading to heating and subsequent O + escape supporting the ∼10 25 atoms s −1 (∼0.4 kg/s) O + outflow indicated by present‐day observations. A stronger solar wind and O + source of ∼4 Gyr ago could support losses of ∼100 kg/s, enough to strip Mars' atmosphere or 10 m of water in a ∼0.3 Gyr period. The observational evidence for ion heating is, with current data sets, largely circumstantial so we suggest needed observations.