Some peculiarities of VLF wave propagation in the inner magnetosphere of the Earth

1Mendzhul, DI, 2Agapitov, OV, 1Cheremnykh, OK
1Space Research Institute under NAS and National Space Agency of Ukraine, Kyiv, Ukraine
2Taras Shevchenko National University of Kyiv, Kyiv, Ukraine
Kinemat. fiz. nebesnyh tel (Online) 2013, 29(3):3-20
Start Page: Space Physics
Language: Ukrainian

The non-ducted propagation characteristics of VLF waves in the inner magnetosphere are studied with respect to their frequency, source localization, and initial angle between the wave-normal and background magnetic field. The ray tracing software based on multi-component cold plasma approach is developed with the use of the IGRF magnetic field model and diffusion model of plasma density. We describe the dynamics of the wave-normal direction during propagation and magnetospheric reflection. It is shown that whistler waves can be reflected when lower hybrid resonance frequency becomes greater than the wave frequency ( ωLHF > ω). This corresponds to the magnetic latitude near λ≈ 50°. The simulation results confirm the inapplicability of the quasi-longitudinal approximation to describe the magnetospheric whistler propagation. We present some simulation results of chorus emissions propagation on the basis of realistic wave distributions on the initial parameters. Particularly, distributions of chorus emission waves in accordance with the wave-normal directions are obtained for different magnetic latitudes. These distributions are required for studying diffusive processes in the radiation belts. Our results are in good agreement with the CLUSTER STAFF-SA measurements.

Keywords: Earth, inner magnetosphere, VLF waves

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