Project MONICA for the Study of Time-Variable Phenomena of the Jovian Sodium Cloud and the Io Plasma Torus

Because of active volcanism, large amounts of gas and dust particles are being injected from the Galilean satellite, Io, into the Jovian system. The neutral cloud of sodium atoms and the plasma torus of sulfur ions provide very useful information on Io’s interaction with the Jovian magnetosphere. A program called MONICA (Monitoring of Neutral and Ionized Atoms Clouds) was established at NCU with a view to participate in an international campaign during the flyby of the Jovian system by the Cassini spacecraft in December, 2000. Spectrographic observations were carried out using the 2.16m spectrograph of the Beijing Astronomical Observatory in Xing-Long. A progress report is presented here.