Field-Aligned Propagation of Whistler-Mode Waves in Radiation Belt

Propagation of ELF/VLF whistler-mode waves along the ambient magnetic field is the question of great interest and importance for a quantitative understanding of the wave-particle interactions in the Earth magnetosphere.Particularly, this subject is important for the development of comprehensive numerical and theoretical models describing electromagnetic fields and energetic electrons in the Earth radiation belt.Observations from NASA Van Allen Probes and Magnetospheric Multiscale (MMS) satellites demonstrate that whistler-mode waves can be guided along the ambient magnetic field by the field-aligned irregularities of the plasma density and the magnetic field.These irregularities can be formed by the depletion of the plasma density or the magnetic field (these are low-density or low-B ducts), enhancement (high-density or high-B ducts) and shelf-like density and magnetic field structures.The ducting of the whistler-mode waves explains their propagation in the Earth's magnetosphere over a significant distance with a little attenuation, which was observed in recent experiments with the DSX satellite.