Statistical Distribution of Electromagnetic Ion Cyclotron (EMIC) Waves in Jupiter’s Magnetosphere

Electromagnetic ion cyclotron (EMIC) waves scatter electrons and ions into the atmosphere through gyro-resonant interactions, making them important for understanding planetary aurorae, such as Jupiter's X-ray aurora. In this study, we use magnetic field measurements from the fluxgate magnetometer onboard the Juno spacecraft during 2016–2022 to provide statistical distribution of EMIC waves in Jupiter's magnetosphere. The results show that EMIC waves at Jupiter are observed across four ion bands: He+, O++, O+/S++, and S+, the O++ band being the most abundant. All four banded EMIC waves are more abundant on the dawnside than the duskside and confined within ±20 RJ (Jupiter radii) of the equatorial plane. S+ band EMIC waves are confined close to the planet (within ±60 RJ), while the other three bands are spread out radially. The occurrence of different banded EMIC waves varies with radial distance, consistent with the distribution of the ions that generate them.