Statistical Survey of Electron Cyclotron Harmonic Waves and Whistler Waves Modulated by Ultra-low-frequency Waves

Magnetopause perturbations by solar wind transients drive a wide variety of ultra-low-frequency (ULF) waves in Earths magnetosphere. These waves can modulate thermal and energetic electron fluxes, changing their flux anisotropy. Such modulation may drive electron distributions beyond the threshold of instabilities responsible for the generation of electron cyclotron harmonic (ECH) and whistler waves, which are often observed in association with compressional ULF waves. Given the importance of ECH and whistler-mode waves for electron acceleration, scattering, and loss to the atmosphere, here we statistically investigate the main characteristics of ULF-modulated ECH and whistler waves. We find two main types of events: with the correlation of whistler-mode and ECH waves and with their anti-correlation. We present spatial distribution of these two types of events and examine correlations of background plasma/magnetic field characteristics with properties of whistler and ECH waves modulated by ULF waves.