Y. Miyoshi(1), H.Misawa(1), A.Morioka(1), T. Kondo(2), Y. Koyama(2) and J. Nakajima(2)
(1) Upper Atmosphere and Space Research Loboratary, Tohoku University, Sendai 980-8578, Japan, (2) Kashima Space Research Center, Communications Research Laboratory, Kashima 314-0012, Japan.
miyoshi(AT)stpp2.geophys.tohoku.ac.jp /Fax:[+81] 22-217-6406
The time variation of synchrotron component of Jovian decimetric radiation (DIM) reflects the generation and dissipation processes of relativistic electrons in the Jupiter's inner radiation belt. Although the discovery of DIM was in the late 1950's, there are few observations which have the information on the dynamics of the inner Jovian radiation belt. In particular, the existence of short-term (days~week) variation of DIM flux has been never confirmed.
We have made the radio flux measurements at 2290MHz with the 34m radio telescope of KSRC, CRL from Nov.12, 1996 to Nov.24, 1996 and the 64m radio telescope of UDSC, ISAS once a few weeks from May, l996 to Nov., 1996. As a result, more than 10% flux enhancement with a few days duration was confirmed on the KSRC observation. The data also showed the changes of the magnetic latitude beaming curves in this period. Since it is difficult to consider that the short-term variation is caused by the particle injection process from the outer magnetosphere, this observational result may indicate the existence of rapid fluctuations of relativistic electrons in the inner radiation belt. We show the method of observations and analyzed results in our presentation.