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Origin and interrelation of discrete and noise- like ELF/VLF emissions in the Earth's magnetosphere, and their role in the acceleration and loss of radiation belt electrons


The project is aimed to study acceleration of relativistic electrons and generation and propagation of chorus and other ELF/VLF discrete emissions in the Earth magnetosphere by joint theoretical and experimental investigations.

Theoretical study of coherent and stochastic acceleration of relativistic electrons in the process of their resonant cyclotron interaction with whistler-mode waves with changing frequency will be performed. These acceleration mechanisms will be incorporated into a common self-consistent scheme of radiation belt formation. Energy and particle budgets of radiation belts, with account of cyclotron acceleration and precipitation will be considered.

The problem of generation and propagation of chorus and other ELF/VLF discrete emissions in the magnetosphere will be analysed theoretically using both analytical and computational approaches. For that purpose, semi-empirical and strict theoretical models of chorus generation will be developed. Properties of ducted and non-ducted propagation of whistler waves will be analysed. Formation of coherent clusters from noise in coupled electron and whistler wave phase space will be studied. Triggering of ELF/VLF emissions by whistlers from lightning discharges and by power line harmonics will be investigated.

The theoretical analysis of all problems will be complemented, supported, and tested with the help of extensive plasma and particle simulations.

An important part of this project is verification of theoretical results with statistical and case studies of experimental data. Experimental studies in the project will include the analysis of recent measurements from MAGION 4-5, Cluster and other satellites. Detailed quantitative comparison of the elaborated theoretical models of chorus generation with experimental data on wave spectral, spatial, and temporal characteristics will be made. Cold plasma and energetic electron data will be analysed to verify the chorus generation theory and to investigate the coherent acceleration mechanism of relativistic electrons. Modern methods will be applied for analysis of satellite and ground-based data.

New and principal results that will be obtained during this project will deal with the origin and effects of ELF/VLF chorus emissions - the most intense electromagnetic radiation in near-Earth space. Their role is crucial in formation of the relativistic electron component of the radiation belts. The direct connection between chorus generation and the increase of fluxes of relativistic electrons is confirmed by experiment, and quantitative relations between chorus intensity and flux density of relativistic electrons on local and global scales will be obtained. The results should help to make a quantitative forecast of when, where and to what degree the intensity of relativistic electron fluxes will change with the intensity and the phase of a magnetic storm, which is the main contributory factor to space weather.


Southampton University
SO17 1BJ Southampton
United Kingdom

Participants (7)

Academy of Sciences of the Czech Republic Institute of Atmospheric Physics
Bocni Ii 1401
14131 Prague
Charles University
V. Holesovickach 2
18000 Prague
United Kingdom
The Gateway
LE1 9BH Leicester
Kola Scientific Center, Russian Academy of Sciences Polar Geophysical Institute
Fersman 14
184200 Apatity
Russian Academy of Sciences Institute of Applied Physics
Ulyanov Str. 46
603950 Nizhny Novgorod
Russian Academy of Sciences Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation
Pushkovyh Str.
142190 Troitsk
University of Oulu
Tahtelantie 62
99600 Sodankyla