Sector boundary passages and Jupiter's decametric radiation.

This thesis presents descriptions of phenomena, namely, interplanetary magnetic field (IMF) sector boundary crossings, radial diffusion and the wave conversion mechanism, that have important places in the explanation of the phenomenology and the fine structure of Jovian decametric (DAM) emission. The IMF sector structure is examined first. Assuming that this sector structure is co-rotating with the Sun, we have found the triggering effect of the IMF sector boundary crossings on Jovian DAM emission. Histograms (number of occurrences versus the time with respect to sector boundary passage) show peaks within one or two days following the sector boundary. Next, the question of radial diffusion is reviewed. Using the Pioneer 10 and Pioneer 11 data on the plasma parameters and magnetic field of Jupiter, we have found the phase-space density profile of the inner-radiation belt, [special character omitted], and have compared it with the observational results. Our theoretical result is consistent with the observations, and has been used in the wave conversion problem. Finally, "cold" and ''warm" plasma models have been used to solve the wave equation. By "matching" the two solutions, we have obtained information about the "transition region". The wave conversion mechanism has given us an insight into the fine structure of Jovian dynamic spectra, such as the "modulation lanes". Finally, the role of asymptotic solutions for obtaining more accurate results is considered.