Search for Jovian hectometric and kilometric radiation by GEOTAIL spacecraft during the impact of Comet Shoemaker-Levy 9

We made a survey for Jovian hectometric and kilometric radiation by GEOTAIL spacecraft before, during, and after the impacts of Comet Shoemaker-Levy 9 (SL-9). We attempted to identify the radiation from Jupiter based on a k vector determination. However, we did not find clear enhancement of the Jovian radiation activity in the whole period nor around each impact time. With regard to the Jovian magnetospheric activity, the enhancement of synchrotron and X-ray radiation in association with the SL-9 event has been already reported. Synchrotron radiation increased during the week of the impacts, and X-rays was clearly detected just around K impact time at the magnetic conjugate footprints of the impact sites. This suggests that a strong perturbation at the impact sites has given non negligible change in the inner magnetosphere directly or indirectly. Our results suggest that such activities were limited in the inner magnetosphere only on low L shells, and there were few amount of direct coupling between the cometary fragments and the Jovian outer magnetosphere. This is consistent with the ground-based observation of the decametric radiation that no significant change was detected during the SL-9 event.