Jovian dual‐sinusoidal HOM Lane features observed by Galileo

A well defined sinusoidal‐shaped “band” of reduced emission intensity exists within Jovian HOM from 500 kHz to 3 MHz at all Jovian longitudes as observed by the Galileo spacecraft. A less prominent sinusoidal‐shaped band feature exists in the same frequency range but is 180° out of phase with the more prominent feature. We used a multiple Jovian rotation spectrogram technique to fully display both bands and found that these sinusoidal‐shaped features are the source of the “lanes” previously studied in Voyager and Ulysses data. Our extension of the simple straight‐line ray model by Gurnett et al. [1998] provides a qualitative explanation for the observed features. We found that the two sinusoidal bands show an asymmetry about the longitude of the northern tip of the magnetic dipole (202° CML). Enhancements of emission can be seen along the edges of the bands which may be interpreted as caustic surfaces.