  The narrowband kilometric radiation (nKOM) is a Jovian low-frequency radio
component identified as a plasma emission produced in the region of the Io
plasma torus. Measurements from the Waves instrument onboard the Juno
spacecraft permitted to establish the distribution of nKOM occurrence and
intensity as a function of frequency and latitude. We have developed a 3D
geometrical model that can simulate at large scale the plasma emissions
occurrence observed by a spacecraft based on an internal Jovian magnetic field
model and a diffusive equilibrium model of the plasma density in Jupiter's
inner magnetosphere. With this model, we propose a new method to discriminate
the generation mechanism, wave mode, beaming and radio source location of
plasma emissions. Here, this method is applied to the study of the nKOM
observed from all latitudes by the Juno/Waves experiment to identify which
conditions reasonably reproduce the observed occurrence distribution versus
frequency and latitude. The results allow us to exclude the two main nKOM
models published so far, and to show that the emission must be produced at the
local plasma frequency and beamed along its local gradient in the direction of
decreasing frequencies. We also propose that depending on its latitude, Juno
observes two distinct kinds of nKOM: the low frequency nKOM in ordinary mode at
high latitudes and high frequency nKOM on extraordinary mode at low latitudes.
Both radio source locations are found to be distributed near the centrifugal
equator from the outer edge to the inner edge of the Io plasma torus.
