  The atmospheric circulation in the upper atmosphere of hot Jupiter planets is
strongly influenced by the incoming stellar radiation. In this work we explore
the results from a 3D atmospheric model and revisit the main processes driving
the circulation in hot Jupiter planets. We use the angular momentum transport
as a diagnostic and carry out a Fourier analysis to identify the atmospheric
waves involved. We find that the coupling between the angular momentum
transported horizontally by the semi-diurnal tide and the mean circulation is
the mechanism responsible for producing the strong jet at low latitudes. Our
simulations indicate the possible formation of atmospheric indirect cells at
low latitudes. The formation of these cells is induced by the presence of the
semi-diurnal tide that is driven by the stellar irradiation. The tropical
circulation has an important impact transporting heat and momentum from the
upper towards the lower atmosphere. One of the consequences of this heat and
momentum transport is a global increase of the temperature. We show that the
initial conditions do not affect the output of the reference simulation.
However, when the period of rotation of the planet was increased ($P_{rot} > 5$
Earth days), vertical transport by stationary waves became stronger, transient
waves became non-negligible, and Coriolis influence less dominant, which
allowed a steady state with a strong retrograde jet to be stable. We found that
at least two statically steady state solutions exist for the same planet
parameters.
