Local Time Occurrence of Solar Type III Bursts at Saturn’s Orbit. Planetary Radio Emissions| PLANETARY RADIO EMISSIONS VII 7|

Abstract

We report on solar radio bursts observed by the RPWS experiment on board the Cassini spacecraft in the period from 1st January 2004 to 31st March 2010. In this time intervals of about six years a limited number of strong solar type III bursts, less than 300, has been recorded. This is mainly due to the solar activity which reaches its minimum in 2008–2009. In this study we consider type III solar bursts observed at frequencies lower than 1.2 MHz generated in the interplanetary medium. We analyse the solar bursts with the aim to estimate the Cassini local time (LT) occurrence rate, where the Kronian day has been divided into eight LT sectors. Our results are combined with the Cassini orbits where the LT and the distance to the planet are taken into consideration. We show that the type III burst occurrence rates depend on the solar activity, however the day side sector (midday to early afternoon) exhibits the lowest rate of occurrence