The question of how continuum radiation trapped in Jupiter's magnetosphere might be generated is considered. It is shown that the efficiency of the linear conversion is not sufficient to account for the observed intensity of the emission. We discuss nonlinear processes that can more easily provide the required conversion efficiency. The field strengths of upper hybrid waves required to generate the fundamental harmonic emissions are ~0.5¿4 mV m-1. Comparison of the results of the discussed model with electric fields reported in the Jovian magnetosphere shows that the model adequately explains the generation of continuum radiation trapped in the planetary cavity. ¿ 2001 American Geophysical Union