Review of Controlled Excitation of Non-linear Wave-Particle Interactions in the Magnetosphere
Controlled experiments involving injection of 0.5 Hz–8 kHz electromagnetic waves into the Earth's magnetosphere have played an important role in discovering and elucidating wave-particle interactions in near-Earth space. Due to the significant engineering challenges of efficiently radiating in...
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2019-02-01
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| Series: | Frontiers in Astronomy and Space Sciences |
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| Online Access: | https://www.frontiersin.org/article/10.3389/fspas.2019.00002/full |
| _version_ | 1819055601990238208 |
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| author | Mark Gołkowski Vijay Harid Poorya Hosseini |
| author_facet | Mark Gołkowski Vijay Harid Poorya Hosseini |
| author_sort | Mark Gołkowski |
| collection | DOAJ |
| description | Controlled experiments involving injection of 0.5 Hz–8 kHz electromagnetic waves into the Earth's magnetosphere have played an important role in discovering and elucidating wave-particle interactions in near-Earth space. Due to the significant engineering challenges of efficiently radiating in the ELF/VLF: 300 Hz–30 kHz band, few experiments have been able to provide sustained transmissions of sufficient power to excite observable effects for scientific studies. Two noteworthy facilities that were successful in generating a large database of pioneering and repeatable observations were the Siple Station Transmitter in Antarctica and the High Frequency Active Auroral Research Program (HAARP) facility in Alaska. Both facilities were able to excite Doppler shifted cyclotron resonance interactions leading to linear and non-linear wave amplification, triggering of free running emissions, and pitch angle scattering of energetic electrons. Amplified and triggered waves were primarily observed on the ground in the geomagnetic conjugate region after traversal of the magnetosphere along geomagnetic field aligned propagation paths or in the vicinity of the transmitter following two traversals of the magnetosphere. In several cases, spacecraft observations of the amplified and triggered signals were also made. The observations show the amplifying wave particle interaction to be dynamically sensitive to specific frequency and also specific frequency-time format of the transmitted wave. Transmission of multiple coherent waves closely spaced in frequency showed that the wave particle interaction requires a minimum level of coherency to enter the non-linear regime. Theory and numerical simulations point to cyclotron resonance with counter streaming particles in the 10–100 keV range as the dominant process. A key feature of the non-linear interaction is the phase-trapping of resonant particles by the wave that is believed to drive non-linear wave amplification and the triggering of free-running emissions. Observations and modeling of controlled wave injections have important implications for naturally occurring whistler mode emissions of hiss and chorus and the broader phenomena of radiation belt dynamics. A review of observational, theoretical, and numerical results is presented and suggestions for future studies are made. |
| first_indexed | 2024-12-21T13:10:07Z |
| format | Article |
| id | doaj.art-97a67074669e4e57a8cbedacd74d2658 |
| institution | Directory Open Access Journal |
| issn | 2296-987X |
| language | English |
| last_indexed | 2024-12-21T13:10:07Z |
| publishDate | 2019-02-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Astronomy and Space Sciences |
| spelling | doaj.art-97a67074669e4e57a8cbedacd74d26582022-12-21T19:02:54ZengFrontiers Media S.A.Frontiers in Astronomy and Space Sciences2296-987X2019-02-01610.3389/fspas.2019.00002428572Review of Controlled Excitation of Non-linear Wave-Particle Interactions in the MagnetosphereMark GołkowskiVijay HaridPoorya HosseiniControlled experiments involving injection of 0.5 Hz–8 kHz electromagnetic waves into the Earth's magnetosphere have played an important role in discovering and elucidating wave-particle interactions in near-Earth space. Due to the significant engineering challenges of efficiently radiating in the ELF/VLF: 300 Hz–30 kHz band, few experiments have been able to provide sustained transmissions of sufficient power to excite observable effects for scientific studies. Two noteworthy facilities that were successful in generating a large database of pioneering and repeatable observations were the Siple Station Transmitter in Antarctica and the High Frequency Active Auroral Research Program (HAARP) facility in Alaska. Both facilities were able to excite Doppler shifted cyclotron resonance interactions leading to linear and non-linear wave amplification, triggering of free running emissions, and pitch angle scattering of energetic electrons. Amplified and triggered waves were primarily observed on the ground in the geomagnetic conjugate region after traversal of the magnetosphere along geomagnetic field aligned propagation paths or in the vicinity of the transmitter following two traversals of the magnetosphere. In several cases, spacecraft observations of the amplified and triggered signals were also made. The observations show the amplifying wave particle interaction to be dynamically sensitive to specific frequency and also specific frequency-time format of the transmitted wave. Transmission of multiple coherent waves closely spaced in frequency showed that the wave particle interaction requires a minimum level of coherency to enter the non-linear regime. Theory and numerical simulations point to cyclotron resonance with counter streaming particles in the 10–100 keV range as the dominant process. A key feature of the non-linear interaction is the phase-trapping of resonant particles by the wave that is believed to drive non-linear wave amplification and the triggering of free-running emissions. Observations and modeling of controlled wave injections have important implications for naturally occurring whistler mode emissions of hiss and chorus and the broader phenomena of radiation belt dynamics. A review of observational, theoretical, and numerical results is presented and suggestions for future studies are made.https://www.frontiersin.org/article/10.3389/fspas.2019.00002/fullwhistler anisotropy instabilitytriggered emissionswhistler mode chorus wavesactive experimentsHAARP facilityradiation belts |
| spellingShingle | Mark Gołkowski Vijay Harid Poorya Hosseini Review of Controlled Excitation of Non-linear Wave-Particle Interactions in the Magnetosphere Frontiers in Astronomy and Space Sciences whistler anisotropy instability triggered emissions whistler mode chorus waves active experiments HAARP facility radiation belts |
| title | Review of Controlled Excitation of Non-linear Wave-Particle Interactions in the Magnetosphere |
| title_full | Review of Controlled Excitation of Non-linear Wave-Particle Interactions in the Magnetosphere |
| title_fullStr | Review of Controlled Excitation of Non-linear Wave-Particle Interactions in the Magnetosphere |
| title_full_unstemmed | Review of Controlled Excitation of Non-linear Wave-Particle Interactions in the Magnetosphere |
| title_short | Review of Controlled Excitation of Non-linear Wave-Particle Interactions in the Magnetosphere |
| title_sort | review of controlled excitation of non linear wave particle interactions in the magnetosphere |
| topic | whistler anisotropy instability triggered emissions whistler mode chorus waves active experiments HAARP facility radiation belts |
| url | https://www.frontiersin.org/article/10.3389/fspas.2019.00002/full |
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