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A model analysis of Galileo electron densities on Jupiter
Author(s) -
Majeed T.,
McConnell J. C.,
Gladstone G. R.
Publication year - 1999
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 - 10.1029/1999gl900530
Subject(s) - jovian , ionosphere , altitude (triangle) , jupiter (rocket family) , atmospheric sciences , electron density , physics , electron , excited state , atmosphere of jupiter , computational physics , plasma , geophysics , atomic physics , astrophysics , astronomy , planet , geometry , saturn , mathematics , space shuttle , quantum mechanics
A one‐dimensional chemical‐diffusive model of the Jovian ionosphere, in conjunction with measured upper atmospheric temperatures, is used to analyze the upper ionospheric electron densities on Jupiter measured by the Galileo RSS instrument on December 8, 1995. The analyses of these measurements have yielded quite different ionospheric properties at ingress and egress in terms of both the magnitude and the altitude of the peak electron density (n e ). At ingress, the peak n e was ∼10 5 cm −3 at an altitude of ∼900 km. However, at egress the n e peak was ∼5 times smaller than at ingress and was located at ∼1800 km altitude. As with our previous studies, we find it necessary to invoke a combination of vibrationally excited H 2 and vertical plasma flow to explain the measured ionospheric structure. The most interesting conclusion of this study is that a downward drift of plasma is required to fit the peak altitude of the ingress n e profile. The direction of the vertical flow is most likely determined by the horizontal neutral wind. At egress, the situation is quite different because a strong field‐aligned drift of 90 m/s, most likely caused by the meridional component of the neutral wind, is required to maintain the peak n e at the measured altitude. The role of vibrationally excited H 2 in determining the magnitude of the measured n e appears to be less important at ingress than at egress.