Dr. Carr will continue research toward understanding the emission from Jupiter which occurs at relatively long wavelengths. He will broaden a monitoring program that has been conducted at the University of Florida Radio Observatory since 1957, and which includes continuous monitoring of S burst storms with a radio spectrograph of very high sensitivity and resolution and observations with interferometers having baselines of 30 miles east-west and 100 miles north-south. Dr. Carr plans to make a new determination of the rotation period of Jupiter's magnetosphere which should help establish the magnitude of wandering of Jupiter's magnetic pole. A new catalog of S burst storms will be used to test current theories for the emission of S type bursts. Jupiter's decametric wavelength bursts and the bursts from the active Sun are by far the most powerful of the radiations of extraterrestrial origin that are received on Earth. The bursts from Jupiter occur only below a frequency of 40 MHz, and they can be studied from Earth down to about 10 MHz, below which observation is prevented by the effects of the terrestrial ionosphere. The close approach of two Voyager spacecraft to Jupiter in 1979 provided new insights into the phenomenolgy and beaming geometry of the decametric wavelength component. Despite the enormous amount of observational data that resulted from the Voyager encounters, ground-based observations have lost none of their importance. The low frequency radiations from giant planet magnetospheres are still unexplained. We are still in the stage of unraveling the more and more complex phenomenologies of the radiations, but phenomenology and theory are now being tied together. This will be strengthened as ground based monitoring programs span more years, as the observations become more sophisticated, and as the Galileo spacecraft adds important post- Voyager data to what is known about those radiation components that are prevented by the ionosphere from reaching the Earth's surface. Dr. Carr's project is a principal component in the ground-based effort to understand the nature of these long wavelength emissions.
