The results of a computer code modeling the radial diffusion of equatorially confined energetic electrons in Jupiter's inner magnetosphere are compared with spacecraft as well as ground-based radio (synchrotron radiation) data. We find that the synchrotron radiation spectrum cannot be reproduced without a significant hardening of the electron spectrum between L=3 and L=1.5. This hardening may be due to energy degradation by Jupiter's ring particles. Our calculations also suggest that there may be larger-sized material outside Jupiter's ring up to L~4 or Io's orbit. ¿ American Geophysical Union 1990