Fig. 3: Magnified spectral characteristics of discrete whistler-mode wave elements with 1-s resolution.

a Wave damping at half the gyrofrequency. b Rising-tone elements in the lower band. c Falling-tone element in the upper band. The white solid and dotted curves represent the electron gyrofrequency and half the gyrofrequency, respectively, calculated using an empirical magnetic field model36. Source data are provided as a Source Data file.