  The ion temperature of the magnetospheres of Jupiter and Saturn was observed
to increase substantially from about 10 to 30 planet radii. Different heating
mechanisms have been proposed to explain such observations, including a heating
model for Jupiter based on MHD turbulence with flux-tube diffusion. More
recently, an MHD turbulent heating model based on advection was shown to also
explain the temperature increase at Jupiter and Saturn. We further develop this
turbulent heating model by combining effects from both diffusion and advection.
The combined model resolves the physical consistency requirement that diffusion
should dominate over advection when the radial flow velocity is small and vice
versa when it is large. Comparisons with observations show that previous
agreements, using the advection only model, are still valid for larger radial
distance. Moreover, the additional heating by diffusion results in a better
agreement with the temperature observations for smaller radial distance.

Space Physics;Earth and Planetary Astrophysics;Plasma Physics