Survey of Whistler-Mode Wave Amplitudes and Frequency Spectra in Jupiter's Magnetosphere

Abstract

We present statistical distributions of whistler-mode chorus and hiss waves at frequencies ranging from the local proton gyrofrequency to the equatorial electron gyrofrequency (f_ce,eq) in Jupiter's magnetosphere based on Juno measurements. The chorus wave power spectral densities usually follow the f_ce,eq variation with major wave power concentrated in the 0.05f_ce,eq–f_ce,eq frequency range. The hiss wave frequencies are less dependent on f_ce,eq variation than chorus with major power concentrated below 0.05f_ce,eq, showing a separation from chorus at M < 10. Our survey indicates that chorus waves are mainly observed at 5.5 < M < 13 from the magnetic equator to 20° latitude, consistent with local wave generation near the equator and damping effects. The hiss wave powers extend to 50° latitude, suggesting longer wave propagation paths without attenuation. Our survey also includes the whistler-mode waves at high latitudes which may originate from the Io footprint, auroral hiss, or propagating hiss waves reflected to high M shells.