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K. I. Matcheva, D. F. Strobel (Johns Hopkins University), F. M. Flasar (Goddard Space Flight Center)
The J0-ingress radio occultation of the Galileo orbiter by Jupiter exhibits a system of well defined, regularly spaced electron layers in the altitude range, where the presence of gravity waves have been previously inferred. Based on the terrestrial analog of sporadic E and spread F ionospheric layers, it is argued that the observed layers are a result of dynamical processes rather than chemistry. The impact of upward propagating gravity waves on the plasma distribution in a H+ dominated ionosphere is studied as a possible forcing mechanism for the observed ionospheric structure. The relevant physics is discussed and illustrated with an analytic, small amplitude model. A time dependent, 2D, large amplitude model is developed to simulate the observed large excursions in the J0-electron density profile. It is demonstrated that gravity waves with parameters consistent with the thermal structure of Jupiter's upper atmosphere are capable of creating large peaks in the electron density similar to the observed ones. A wave driven plasma flux results in plasma removal above the altitude of maximum ionospheric response and plasma deposition in the region below, significantly modifying the initial steady state electron density profile. Various possible wave propagation scenarios and global implications are explored.
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