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 paper was published as Annales Geophysicae, 2009, 27 (1, Special Issue), pp. 131-145. It is also available from http://www.ann-geophys.net/27/131/2009/angeo-27-131-2009.html. Doi:10.5194/angeo-27-131-2009 Multi-instrument observational data from an experiment on 13 October 2006 at the EISCAT/HE...
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Copernicus Publications on behalf of the European Geosciences Union (EGU)
2010
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Online Access: | http://hdl.handle.net/2381/8173 http://www.ann-geophys.net/27/131/2009/ https://doi.org/10.5194/angeo-27-131-2009 |
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ftleicester:oai:lra.le.ac.uk:2381/8173 2023-05-15T16:04:39+02:00 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 Blagoveshchenskaya, N. F. Carlson, H. C. Kornienko, V. A. Borisova, T. D. Rietveld, M. T. Yeoman, Tim K. Brekke, A. 2010-07-06T14:07:48Z http://hdl.handle.net/2381/8173 http://www.ann-geophys.net/27/131/2009/ https://doi.org/10.5194/angeo-27-131-2009 en eng Copernicus Publications on behalf of the European Geosciences Union (EGU) Radio and Space Plasma Physics Annales Geophysicae, 2009, 27 (1, Special Issue), pp. 131-145. 0992-7689 http://hdl.handle.net/2381/8173 http://www.ann-geophys.net/27/131/2009/ doi:10.5194/angeo-27-131-2009 Article 2010 ftleicester https://doi.org/10.5194/angeo-27-131-2009 2019-03-22T20:14:13Z This paper was published as Annales Geophysicae, 2009, 27 (1, Special Issue), pp. 131-145. It is also available from http://www.ann-geophys.net/27/131/2009/angeo-27-131-2009.html. Doi:10.5194/angeo-27-131-2009 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 of striations, 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 Leicester: Leicester Research Archive (LRA) Norway Tromsø Langmuir ENVELOPE(-67.150,-67.150,-66.967,-66.967) Annales Geophysicae 27 1 131 145 |
institution |
Open Polar |
collection |
University of Leicester: Leicester Research Archive (LRA) |
op_collection_id |
ftleicester |
language |
English |
description |
This paper was published as Annales Geophysicae, 2009, 27 (1, Special Issue), pp. 131-145. It is also available from http://www.ann-geophys.net/27/131/2009/angeo-27-131-2009.html. Doi:10.5194/angeo-27-131-2009 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 of striations, 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 |
Blagoveshchenskaya, N. F. Carlson, H. C. Kornienko, V. A. Borisova, T. D. Rietveld, M. T. Yeoman, Tim K. Brekke, A. |
spellingShingle |
Blagoveshchenskaya, N. F. Carlson, H. C. Kornienko, V. A. Borisova, T. D. Rietveld, M. T. Yeoman, Tim K. Brekke, A. 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 |
author_facet |
Blagoveshchenskaya, N. F. Carlson, H. C. Kornienko, V. A. Borisova, T. D. Rietveld, M. T. Yeoman, Tim K. Brekke, A. |
author_sort |
Blagoveshchenskaya, N. F. |
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 (EGU) |
publishDate |
2010 |
url |
http://hdl.handle.net/2381/8173 http://www.ann-geophys.net/27/131/2009/ https://doi.org/10.5194/angeo-27-131-2009 |
long_lat |
ENVELOPE(-67.150,-67.150,-66.967,-66.967) |
geographic |
Norway Tromsø Langmuir |
geographic_facet |
Norway Tromsø Langmuir |
genre |
EISCAT Tromsø |
genre_facet |
EISCAT Tromsø |
op_relation |
Radio and Space Plasma Physics Annales Geophysicae, 2009, 27 (1, Special Issue), pp. 131-145. 0992-7689 http://hdl.handle.net/2381/8173 http://www.ann-geophys.net/27/131/2009/ doi:10.5194/angeo-27-131-2009 |
op_doi |
https://doi.org/10.5194/angeo-27-131-2009 |
container_title |
Annales Geophysicae |
container_volume |
27 |
container_issue |
1 |
container_start_page |
131 |
op_container_end_page |
145 |
_version_ |
1766400258168848384 |