Phenomena induced by powerful HF pumping towards magnetic zenith with a frequency near the F-region critical frequency and the third electron gyro harmonic frequency
This is the publisher’s version/PDF (published in Annales Geophysicae, an open access journal of the European Geosciences Union) Multi-instrument observational data from an experiment on 13 October 2006 at the EISCAT/HEATING facility at Tromsø, Norway are analysed. The experiment was carried out in...
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ftunivtroemsoe:oai:munin.uit.no:10037/2384 2024-06-02T08:05:58+00:00 Phenomena induced by powerful HF pumping towards magnetic zenith with a frequency near the F-region critical frequency and the third electron gyro harmonic frequency Brekke, Asgeir Blagoveshchenskaya, N. F. Carlson, H. C. Kornienko, V. A. Borisova, T. D. Rietveld, M. T. Yeoman, T. K. 2009-01-08 1432592 bytes application/pdf https://hdl.handle.net/10037/2384 eng eng Copernicus Publications on behalf of the European Geosciences Union Annales Geophysicae, 27, 131–145, 2009 0992-7689 https://hdl.handle.net/10037/2384 URN:NBN:no-uit_munin_2134 openAccess VDP::Mathematics and natural science: 400::Physics: 430::Electronics: 435 Ionosphere Active experiments Radio science Nonlinear phenomena VDP::Mathematics and natural science: 400::Physics: 430::Electromagnetism acoustics optics: 434 Journal article Tidsskriftartikkel Peer reviewed 2009 ftunivtroemsoe 2024-05-07T08:42:34Z This is the publisher’s version/PDF (published in Annales Geophysicae, an open access journal of the European Geosciences Union) Multi-instrument observational data from an experiment on 13 October 2006 at the EISCAT/HEATING facility at Tromsø, Norway are analysed. The experiment was carried out in the evening hours when the electron density in the F-region dropped, and the HF pump frequency fH was near and then above the critical frequency of the F2 layer. The distinctive feature of this experiment is that the pump frequency was just below the third electron gyro harmonic frequency, while both the HF pump beam and UHF radar beam were directed towards the magnetic zenith (MZ). The HF pump-induced phenomena were diagnosed with several instruments: the bi-static HF radio scatter on the London- Tromsø-St. Petersburg path, the CUTLASS radar in Hankasalmi (Finland), the European Incoherent Scatter (EISCAT) UHF radar at Tromsø and the Tromsø ionosonde (dynasonde). The results show thermal electron excitation of the HF-induced striations seen simultaneously from HF bi-static scatter and CUTLASS radar observations, accompanied by increases of electron temperature when the heater frequency was near and then above the critical frequency of the F2 layer by up to 0.4 MHz. An increase of the electron density up to 25% accompanied by strong HF-induced electron heating was observed, only when the heater frequency was near the critical frequency and just below the third electron gyro harmonic frequency. It is concluded that the combined effect of upper hybrid resonance and gyro resonance at the same altitude gives rise to strong electron heating, the excitation ofstriations, HF ray trapping and extension of HF waves to altitudes where they can excite Langmuir turbulence and fluxes of electrons accelerated to energies that produce ionization. Article in Journal/Newspaper EISCAT Tromsø University of Tromsø: Munin Open Research Archive Langmuir ENVELOPE(-67.150,-67.150,-66.967,-66.967) Norway Tromsø |
institution |
Open Polar |
collection |
University of Tromsø: Munin Open Research Archive |
op_collection_id |
ftunivtroemsoe |
language |
English |
topic |
VDP::Mathematics and natural science: 400::Physics: 430::Electronics: 435 Ionosphere Active experiments Radio science Nonlinear phenomena VDP::Mathematics and natural science: 400::Physics: 430::Electromagnetism acoustics optics: 434 |
spellingShingle |
VDP::Mathematics and natural science: 400::Physics: 430::Electronics: 435 Ionosphere Active experiments Radio science Nonlinear phenomena VDP::Mathematics and natural science: 400::Physics: 430::Electromagnetism acoustics optics: 434 Brekke, Asgeir Blagoveshchenskaya, N. F. Carlson, H. C. Kornienko, V. A. Borisova, T. D. Rietveld, M. T. Yeoman, T. K. Phenomena induced by powerful HF pumping towards magnetic zenith with a frequency near the F-region critical frequency and the third electron gyro harmonic frequency |
topic_facet |
VDP::Mathematics and natural science: 400::Physics: 430::Electronics: 435 Ionosphere Active experiments Radio science Nonlinear phenomena VDP::Mathematics and natural science: 400::Physics: 430::Electromagnetism acoustics optics: 434 |
description |
This is the publisher’s version/PDF (published in Annales Geophysicae, an open access journal of the European Geosciences Union) Multi-instrument observational data from an experiment on 13 October 2006 at the EISCAT/HEATING facility at Tromsø, Norway are analysed. The experiment was carried out in the evening hours when the electron density in the F-region dropped, and the HF pump frequency fH was near and then above the critical frequency of the F2 layer. The distinctive feature of this experiment is that the pump frequency was just below the third electron gyro harmonic frequency, while both the HF pump beam and UHF radar beam were directed towards the magnetic zenith (MZ). The HF pump-induced phenomena were diagnosed with several instruments: the bi-static HF radio scatter on the London- Tromsø-St. Petersburg path, the CUTLASS radar in Hankasalmi (Finland), the European Incoherent Scatter (EISCAT) UHF radar at Tromsø and the Tromsø ionosonde (dynasonde). The results show thermal electron excitation of the HF-induced striations seen simultaneously from HF bi-static scatter and CUTLASS radar observations, accompanied by increases of electron temperature when the heater frequency was near and then above the critical frequency of the F2 layer by up to 0.4 MHz. An increase of the electron density up to 25% accompanied by strong HF-induced electron heating was observed, only when the heater frequency was near the critical frequency and just below the third electron gyro harmonic frequency. It is concluded that the combined effect of upper hybrid resonance and gyro resonance at the same altitude gives rise to strong electron heating, the excitation ofstriations, HF ray trapping and extension of HF waves to altitudes where they can excite Langmuir turbulence and fluxes of electrons accelerated to energies that produce ionization. |
format |
Article in Journal/Newspaper |
author |
Brekke, Asgeir Blagoveshchenskaya, N. F. Carlson, H. C. Kornienko, V. A. Borisova, T. D. Rietveld, M. T. Yeoman, T. K. |
author_facet |
Brekke, Asgeir Blagoveshchenskaya, N. F. Carlson, H. C. Kornienko, V. A. Borisova, T. D. Rietveld, M. T. Yeoman, T. K. |
author_sort |
Brekke, Asgeir |
title |
Phenomena induced by powerful HF pumping towards magnetic zenith with a frequency near the F-region critical frequency and the third electron gyro harmonic frequency |
title_short |
Phenomena induced by powerful HF pumping towards magnetic zenith with a frequency near the F-region critical frequency and the third electron gyro harmonic frequency |
title_full |
Phenomena induced by powerful HF pumping towards magnetic zenith with a frequency near the F-region critical frequency and the third electron gyro harmonic frequency |
title_fullStr |
Phenomena induced by powerful HF pumping towards magnetic zenith with a frequency near the F-region critical frequency and the third electron gyro harmonic frequency |
title_full_unstemmed |
Phenomena induced by powerful HF pumping towards magnetic zenith with a frequency near the F-region critical frequency and the third electron gyro harmonic frequency |
title_sort |
phenomena induced by powerful hf pumping towards magnetic zenith with a frequency near the f-region critical frequency and the third electron gyro harmonic frequency |
publisher |
Copernicus Publications on behalf of the European Geosciences Union |
publishDate |
2009 |
url |
https://hdl.handle.net/10037/2384 |
long_lat |
ENVELOPE(-67.150,-67.150,-66.967,-66.967) |
geographic |
Langmuir Norway Tromsø |
geographic_facet |
Langmuir Norway Tromsø |
genre |
EISCAT Tromsø |
genre_facet |
EISCAT Tromsø |
op_relation |
Annales Geophysicae, 27, 131–145, 2009 0992-7689 https://hdl.handle.net/10037/2384 URN:NBN:no-uit_munin_2134 |
op_rights |
openAccess |
_version_ |
1800750853261361152 |