Fig. 1: Simultaneous observations of the energetic electron flux decay and whistler-mode wave enhancement near Europa’s orbit on July 10, 2017.
a The frequency-time spectrogram illustrating the magnetic field power spectral density as observed by the WAVES instrument43. The solid line marks the equatorial electron gyrofrequency (fceq), while the dashed line indicates 0.05fceq. b energy-time spectrograms of averaged electron differential fluxes (jdiff, avg) recorded by the Jupiter Energetic Particle Detector Instruments (JEDI)29. c–e the pitch angle distributions of differential electron flux (jdiff) for three selected electron energies (55, 97, and 170 keV). f the 30 s averaged amplitude of whistler-mode waves (Bw) (upper panel) and the omni-directional electron fluxes (jomni) in the lower panel across the three different energy channels: 55 keV, 97 keV, and 170 keV. Vertical dashed lines mark the interval of interest. The equatorial magnetic field intensity, M-shell (the distance from the magnetic equator to Jupiter’s center, normalized by Jupiter’s radius RJ, where RJ = 71,492 km), magnetic latitude (MLAT), and magnetic local time (MLT) are calculated using the JRM33 internal magnetic field model (order 13)21 and the CON2020 current sheet model22. UT refers to universal time, and R denotes the distance normalized to RJ from Juno to the center of mass of Jupiter. Source data are provided as a Source Data file.
