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The sodium exosphere and magnetosphere of Mercury
Author(s) -
Ip W.H.
Publication year - 1986
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/gl013i005p00423
Subject(s) - exosphere , magnetosphere , sodium , ion , solar wind , atomic physics , energetic neutral atom , physics , plasma , mercury (programming language) , limiting , astrobiology , radiation pressure , photoionization , plume , materials science , astrophysics , ionization , meteorology , quantum mechanics , computer science , programming language , mechanical engineering , engineering , metallurgy
Following the recent optical discovery of intense sodium D‐line emission from Mercury, we explore the scenario of an extended exosphere of sodium and other metallic atoms. It is shown that the strong effect of solar radiation pressure acceleration would permit the escape of Na atoms from Mercury's surface even if they are ejected at velocity less than the surface escape velocity. Fast photoionization of the Na atoms is effective in limiting the tailward extension of the sodium exosphere, however. The subsequent loss of the photoions to the magnetosphere could be a significant source of the magnetospheric plasma. The recirculation of the magnetospheric charged particles to the planetary surface could also play an important role in maintaining an extended sodium exosphere as well as a magnetosphere of sputtered metallic ions.