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Non-linear wave interaction, plasma structuring, and electron acceleration in the ionosphere, modified by powerful radio waves


The scientific objective of the proposed project is the study of non-linear processes within the framework of ionospheric modification at middle and high latitudes.

The proposal concentrates on the following topics:

- Non-linear structuring of the ionospheric plasma under the action of a powerful HF electromagnetic wave.

- High-frequency plasma turbulence, excited by powerful HF electromagnetic waves.

- Acceleration of electrons by high-frequency plasma turbulence.

- Impact of powerful HF radio waves in the near-Earth space environment.

Each of these topics will be addressed both theoretically and experimentally to a large extent. For the experiments, both the Sura and Tromso heating facilities will be used. The project will encompass future HF pumping experiments as well as results from past experiments performed by the present collaboration.

The trapping of electrostatic waves in non-linear plasma structures, and the bunching of small-scale structures into large-scale structures, are major theoretical and experimental questions. Incoherent scatter radar, Bragg scatter of HF waves measured with the UTR-2 radio telescope at Kharkov, satellite radio tomography, and the diagnostic SEE method will be the major experimental techniques to be used. The stimulated emission of electromagnetic waves (SEE) is one important manifestation of high-frequency plasma turbulence. Correspondingly, SEE experiments will be central to this research subject. The identification of specific wave interaction processes for specific SEE features, particularly those occurring at frequencies close to electron gyroharmonics, will be one of the important goals.

Another manifestation of high-frequency turbulence is the acceleration of electrons to energies sufficiently high to excite optical emissions, enhance the energies of thermal Langmuir waves, and give rise to the phenomenon known as additional ionisation. Optical observations will concentrate on resolving the vertical structure of the emissions, while incoherent scatter radar measurements will attempt to directly detect and localize enhanced thermal Langmuir waves.

HF pumping experiments in the polar ionosphere constitute a powerful tool for establishing the role of the auroral ionosphere in changes in the magnetospheric-ionospheric system leading to substorm onsets. The problem of the magnitude and nature of the modification effects on the ionosphere-magnetosphere system and the natural response to this man-made impact is not completely understood. In the framework of the proposed project it is planned to investigate phenomena induced by powerful HF radio waves in the nightside auroral ionosphere and to develop a phenomenological model for triggering the auroral activations. The expected results have significant potential in different areas of physics and technology.


Swedish Institute of Space Physics (IRFU)
Lagerhyddsvagen 1
SE-75221 Uppsala

Participants (9)

Lancaster University
United Kingdom
Fylde Avenue 11
LA1 4YR Lancaster
Max-Planck-Gesellschaft Max-Planck-Institut fuer Aeronomie
Max-planck-str. 2
37191 Katlenburg-lindau
Ministry of High Education Radiophysical Research Institute
Bolshaya Pecherskaya Str. 25
603950 Nizhny Novgorod
National Academy of Scienses of Ukraine Institute of Radio Astronomy
Chervonopraporna Str. 4
310002 Kharkov
Rosgidromet Arctic and Antarctic Research Institute
Bering Str. 38
199397 St.-petersburg
Russian Academy of Sciences P.N. Lebedev Physical Institute
Leninskii Pr. 53
119991 Moscow
Russian Academy of Sciences Polar Geophysical Institute
Khalturina Str. 15
183010 Murmansk
Prestvannvegen, 38
University of Oslo
Blindern 15
0316 Oslo