[Previous] | [Session 48] | [Next]

[48.01] Ionospheric Effects on the Propagation and Dissipative Heating of Gravity Waves in Jupiter's Upper Atmosphere

G. Schubert (Dept. Earth and Space Sciences, UCLA), M. P. Hickey (Dept. of Physical Sciences, Embry-Riddle Aeronautical U.), R. L. Walterscheid (The Aerospace Corporation)

We use a full-wave numerical model, including effects of ion-neutral collisions, to study the propagation and dissipation of two gravity waves in Jupiter's thermosphere. A Chapman profile is used to model the electron density profile with parameters adjusted to provide a fit to observations. Ionosphere models dominated by either H or H₃⁺ ions are considered. Both of the modeled waves are significantly affected by the inclusion of ion-neutral collisions. The first gravity wave is more influenced by ion drag when the maximum electron density occurs at low altitudes because this wave is viscously damped at low altitudes. The inclusion of ion drag significantly effects the dissipation of the second gravity wave because it is viscously damped in the region where maximum electron and ion densities occur. Joule dissipation of the currents driven by this gravity wave provides a heating that, in addition to viscous heating, dominates over the cooling associated with sensible heat flux divergence and leads to a net heating of the thermosphere. With the inclusion of ion drag, the contribution of this gravity wave to the observed temperature profile is more significant than previously determined. Wave heating is significantly greater in the H⁺ ionosphere compared to the H₃⁺ ionosphere because the neutral-ion collision frequency is larger for the lighter ion. Our simulations are primarily for low latitudes because wave parameters were inferred from low latitude Galileo Probe observations. We also performed simulations for high latitudes that reveal a strong dependence on magnetic field orientation (which significantly increases ion drag) and Coriolis force (which tends to decrease vertical wavelength and increase molecular dissipation). The contribution of the dissipating gravity waves to the temperature profile is significantly greater at high latitudes.

[Previous] | [Session 48] | [Next]

Bulletin of the American Astronomical Society, 35 #4
© 2003. The American Astronomical Soceity.