Magnetospheric Chorus Emissions : a Review
نویسنده
چکیده
A review of chorus emissions observed on ground-based stations and in the Earth’s magnetosphere is presented. Different approaches to modelling these emissions are discussed. It is pointed out that the most likely energy source of chorus emissions lies in the anisotropic hot electrons in the equatorial magnetosphere. The energy of these electrons is transferred to waves via the electron cyclotron instability. Then the non-linear deformation of the hot electron distribution function under the influence of these waves produces almost monochromatic wavelets which, in their turn, generate a chorus element in a manner similar to the generation of artificially stimulated emissions by ground-based transmitters.
منابع مشابه
Unique concurrent observations of whistler mode hiss, chorus, and triggered emissions
We present a unique 2 h ground-based observation of concurrent magnetospheric hiss, chorus, VLF triggered emissions as well as ELF/VLF signals generated locally by the High Frequency Active Auroral Research Program (HAARP) facility. Eccentricity of observed wave polarization is used as a criteria to identify magnetospheric emissions and estimate their ionospheric exit points. The observations o...
متن کاملLaboratory simulation of magnetospheric chorus wave generation
Whistler mode chorus emissions with a characteristic frequency chirp are important magnetospheric waves, responsible for the acceleration of outer radiation belt electrons to relativistic energies and also for the scattering loss of these electrons into the atmosphere. A laboratory experiment (Van Compernolle et al 2015 Phys. Rev. Lett. 114 245002, An et al 2016 Geophys. Res. Lett.) in the larg...
متن کاملExcitation of Chirping Whistler Waves in a Laboratory Plasma.
Whistler mode chorus emissions with a characteristic frequency chirp are important magnetospheric waves, responsible for the acceleration of outer radiation belt electrons to relativistic energies and also for the scattering loss of these electrons into the atmosphere. Here, we report on the first laboratory experiment where whistler waves exhibiting fast frequency chirping have been artificial...
متن کاملRay tracing of whistler-mode chorus elements: implications for generation mechanisms of rising and falling tone emissions
Using a well-established magnetospheric verylow-frequency (VLF) ray tracing method, in this work we trace the propagation of individual risingand fallingfrequency elements of VLF chorus from their generation point in the equatorial region of the magnetosphere through to at least one reflection at the lower-hybrid resonance point. Unlike recent work by Bortnik and co-workers, whose emphasis was ...
متن کاملDependence of the Sweep Rate of Whistler-mode Chorus Emissions on the Plasma Density
Whistler-mode chorus consists of intense electromagnetic wave packets generated by a nonlinear mechanism involving wave-particle interactions. Chorus wave packets are discrete frequency-time structures in a frequency range from a few hundreds of Hz to several kHz changing their frequency on a time scale from a few tenths of seconds to a few seconds. The source region of chorus emissions is loca...
متن کامل