Cassini Radio and Plasma Wave Science (RPWS) Image Release from Jupiter Observations

This color display is a kind of “voice print” which shows the variation in strength of radio emissions in both frequency (like a set of stations on a radio dial) and time. Strength is represented by color with red being strongest and blue weakest. The radio frequency increases along the vertical axis of the display from bottom to top and time increases
along the horizontal axis from left to right. It is called Spacecraft Event Time (SCET for short).

Depicted here are three examples of radio signals from Jupiter dubbed Jovian Type III bursts. The name comes from a radio astronomical term for certain solar emissions which have a similar shape when displayed in a frequency-time display like this. This type of emission was discovered in Voyager data obtained in 1979. The emissions have also been observed by Ulysses and Galileo. Very little is understood about these emissions; they often occur periodically, sometimes coming every 15 minutes and sometimes every 40 minutes. Those which occur every 40 minutes have been associated with bursts of energetic particles originating near Jupiter. However, we do not know exactly where these emissions are generated or how. We hope that Cassini measurements like these will help to answer some of our questions about their origin.

Contact Information:
Prof. Donald A. Gurnett
donald-gurnett@uiowa.edu
Dr. William Kurth
william-kurth@uiowa.edu
Department of Physics and Astronomy
University of Iowa
Van Allen Hall
Iowa City, IA 52242
Website: http://www-pw.physics.uiowa.edu/plasma-wave/cassini/home.html