Broad band incoherent electromagnetic waves, called hiss, have been detected in the inner zone magnetosphere (L10-6 &ggr;2/Hz at the start of storm recovery phases, 10-7-10-6 &ggr;2/Hz during substorms, and 0.4 to >3.1 MeV from L=2 to L=1.1, respectively. Characteristic lifetimes of inner zone electrons, calculated in order of magnitude fashion on the basis of pitch angle diffusion into the loss cone driven by the cyclotron resonant interaction, are found to range between 10 and 60 days. These computed lifetimes are consistent with observations of enhanced electron precipitation for L>1.25 during storms. Although Coulomb scattering appears to be the dominant loss mechanism for L<1.25, pitch angles scattering by the hiss may make a significant contribution to electron losses, especially during magnetically active intervals. The source of inner zone hiss has also been investigated. Two possible mechanisms of locally generating hiss in the inner zone, an electron cyclotron instability and a Landau resonance, are studied but are found to be unlikely candidates to give rise to hiss. Most features of inner zone hiss can be explained by the hypothesis that hiss originates in the vicinity of the plasmapause as plasmaspheric hiss, which is then able to propagate into the inner zone. There are two major effects that will allow this to occur during storms and substorms. The first is the intensification of plasmaspheric hiss as the freshly injected electrons convect and drift across the plasmapause into the high-density plasmasphere, leading to cyclotron instability. The second is the displacement of the plasmapause, and the presumed source region, to low L values during strong magnetic activity. This reduces the length of the ray paths leading to the inner zone and hence the amount of Landau damping. The present observations are compared with this propagation model and the two are found to be in good agreement.