Divine-Garrett model and Jovian synchrotron emission

Simulations of synchrotron emission from relativistic electrons trapped in Jupiter's magnetic field are used to evaluate the energetic electron distri bution of the Divine-Garrett Jupiter radiation belt model at radial distanc es less than 4 Jovian radii. The fundamental characteristic of synchrotron emission, narrow beaming from gyrating electrons, provides the basis for co nstraints on both the magnetic field and the distribution of particles in t he inner magnetosphere. A comparison between model results and observations is presented. The results suggest the Divine Garrett model significantly u nderestimates the number of relativistic electrons (> 1 MeV) present in Jup iter's inner magnetosphere. The results also indicate that the pitch angle distribution of relativistic electrons in the Jovian radiation belts is dif ferent than assumed in the Divine-Garrett model. These results have importa nt implications for the development of self-consistent models of Jupiter's magnetosphere and the planning of future missions requiring close flybys of Jupiter.