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               Jovian magnetospheric plasma
                is coupled to the ionosphere through Alfvén waves.
                Alfvén waves enable the transport of angular momentum
                and energy between the planet and magnetospheric plasma,
                a process that ultimately generates Jupiter's bright
                auroral emissions. However, past the Alfvén radius, the
                location where the radial velocity is greater than the
                Alfvén velocity, magnetospheric plasma is effectively
                decoupled from the planet, with fluctuations in the
                local magnetosphere no longer communicated back to the
                planet. Determining Jupiter's Alfvén surface is critical
                for interpreting drivers of auroral emissions, in situ
                data, and applications of numerical models. Previous
                studies that calculated the location of the Alfvén
                radius assumed an azimuthally symmetric magnetosphere
                and local-time independent magnetic field. Here, we
                employ a statistical description of the magnetic field
                that includes local time effects. We find a minimum
                Alfvén radius of 30 RJ (Jupiter radii) at 6 LT, with
                plasma decoupled from the planet in the post-dusk
                through dawn sector.  Furthermore, no Alfvén radius
                exists within 60 RJ between 8 and 20 LT. At distances
                greater than 50 RJ, the Alfvén travel time is such that
                magnetospheric plasma moves substantially in the
                magnetosphere before angular momentum can be efficiently
                transferred from the atmosphere. Therefore, the angular
                momentum supplied may no longer be sufficient for the
                local conditions. Our results highlight the importance
                of local time considerations in MI coupling studies and
                offer new interpretations for local time dependent
                auroral features, such as the polar collar. 
                 
               
            
            
              
             
            
            
              
             
             
            
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