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Solar wind and extreme ultraviolet modulation of the lunar ionosphere/exosphere
Author(s) -
Freeman John W.
Publication year - 1976
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/gl003i011p00693
Subject(s) - ionosphere , solar wind , neon , atmospheric sciences , exosphere , coronal mass ejection , atmosphere (unit) , physics , extreme ultraviolet , corona (planetary geology) , solar irradiance , environmental science , plasma , astrobiology , astronomy , meteorology , optics , atomic physics , ion , quantum mechanics , argon , venus , laser
The ALSEP/SIDE detectors routinely monitor the dayside lunar ionosphere. Variations in the ionosphere are found to correlate with both the 2800 MHz radio index which can be related to solar EUV and with the solar wind proton flux. For the solar wind, the ionospheric variation is proportionately greater than that of the solar wind. This suggests an amplification effect on the lunar atmosphere due perhaps to sputtering of the surface or, less probably, an inordinate enhancement of noble gases in the solar wind. The surface neutral number density is calculated under the assumption of neon gas. During a quiet solar wind this number agrees with or is slightly above that expected for neon accreted from the solar wind. During an enhanced solar wind the neutral number density is much higher.