First observations of electron gyro-harmonic effects under X-mode HF pumping the high latitude ionospheric F-region
The file associated with this record is embargoed until 12 months after the date of publication. The final published version may be available through the links above. We provide the first experimental evidence of the sensitivity of phenomena induced by extraordinary (X-mode) polarized HF high power...
Published in: | Journal of Atmospheric and Solar-Terrestrial Physics |
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Online Access: | http://www.sciencedirect.com/science/article/pii/S1364682617300834 http://hdl.handle.net/2381/39604 https://doi.org/10.1016/j.jastp.2017.02.003 |
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ftleicester:oai:lra.le.ac.uk:2381/39604 2023-05-15T16:04:40+02:00 First observations of electron gyro-harmonic effects under X-mode HF pumping the high latitude ionospheric F-region Blagoveshchenskaya, N. F. Borisova, T. D. Kalishin, A. S. Yeoman, Timothy K. Häggström, I. 2017-03-30T10:28:54Z http://www.sciencedirect.com/science/article/pii/S1364682617300834 http://hdl.handle.net/2381/39604 https://doi.org/10.1016/j.jastp.2017.02.003 en eng Elsevier Journal of Atmospheric and Solar-Terrestrial Physics, 2017, 155, pp. 36-49 1364-6826 http://www.sciencedirect.com/science/article/pii/S1364682617300834 http://hdl.handle.net/2381/39604 doi:10.1016/j.jastp.2017.02.003 Copyright © 2017, Elsevier. Deposited with reference to the publisher’s archiving policy available on the SHERPA/RoMEO website. Journal Article 2017 ftleicester https://doi.org/10.1016/j.jastp.2017.02.003 2019-03-22T20:22:40Z The file associated with this record is embargoed until 12 months after the date of publication. The final published version may be available through the links above. We provide the first experimental evidence of the sensitivity of phenomena induced by extraordinary (X-mode) polarized HF high power radio waves to pump frequency stepping across the fifth electron gyro-harmonic (5fce) from below to above. The results were obtained at the EISCAT (European Incoherent Scatter Scientific Association) HF heater facility near Tromsø under effective radiated powers of 456–715 MW, when the HF pump wave was transmitted into the magnetic zenith. We have analyzed the behavior and intensities of various spectral lines in the narrowband stimulated electromagnetic emission (SEE) spectra observed far from the heater, HF-enhanced plasma and ion lines (HFPL and HFIL) from EISCAT UHF incoherent scatter radar spectra, and artificial field-aligned irregularities from CUTLASS (Co-operative UK Twin Located Auroral Sounding System) observations, depending on the frequency offset of the pump field relative to the 5fce. At pump frequencies below 5fce the narrowband SEE spectra exhibited very intense so-called stimulated ion Bernstein scatter (SIBS), accompanied by other spectral components, associated with stimulated Brillouin scatter (SBS), which are greatly suppressed and disappeared in the vicinity of 5fce and did not reappear at fH>5fce. As the pump frequency reached 5fce, the abrupt enhancements of the HFPL and HFIL power, the appearance of cascade lines in the plasma line spectra, and the onset of increasing CUTLASS backscatter power occurred. That is opposite to the ordinary mode (O-mode) effects in the vicinity of 5fce. The X-mode pumping at frequencies below and in the vicinity of the fifth electron gyro-harmonic clearly demonstrated an ascending altitude of generation of induced plasma and ion lines from the initial interaction height, whereas for O-mode heating the region of interaction descended. The observations are consistent with the coexistence of the electron acceleration along and across the geomagnetic field at fH<5fce, while only very strong electron acceleration along the magnetic field was observed at fH≥5fce. Peer-reviewed Post-print Article in Journal/Newspaper EISCAT Tromsø University of Leicester: Leicester Research Archive (LRA) Tromsø Journal of Atmospheric and Solar-Terrestrial Physics 155 36 49 |
institution |
Open Polar |
collection |
University of Leicester: Leicester Research Archive (LRA) |
op_collection_id |
ftleicester |
language |
English |
description |
The file associated with this record is embargoed until 12 months after the date of publication. The final published version may be available through the links above. We provide the first experimental evidence of the sensitivity of phenomena induced by extraordinary (X-mode) polarized HF high power radio waves to pump frequency stepping across the fifth electron gyro-harmonic (5fce) from below to above. The results were obtained at the EISCAT (European Incoherent Scatter Scientific Association) HF heater facility near Tromsø under effective radiated powers of 456–715 MW, when the HF pump wave was transmitted into the magnetic zenith. We have analyzed the behavior and intensities of various spectral lines in the narrowband stimulated electromagnetic emission (SEE) spectra observed far from the heater, HF-enhanced plasma and ion lines (HFPL and HFIL) from EISCAT UHF incoherent scatter radar spectra, and artificial field-aligned irregularities from CUTLASS (Co-operative UK Twin Located Auroral Sounding System) observations, depending on the frequency offset of the pump field relative to the 5fce. At pump frequencies below 5fce the narrowband SEE spectra exhibited very intense so-called stimulated ion Bernstein scatter (SIBS), accompanied by other spectral components, associated with stimulated Brillouin scatter (SBS), which are greatly suppressed and disappeared in the vicinity of 5fce and did not reappear at fH>5fce. As the pump frequency reached 5fce, the abrupt enhancements of the HFPL and HFIL power, the appearance of cascade lines in the plasma line spectra, and the onset of increasing CUTLASS backscatter power occurred. That is opposite to the ordinary mode (O-mode) effects in the vicinity of 5fce. The X-mode pumping at frequencies below and in the vicinity of the fifth electron gyro-harmonic clearly demonstrated an ascending altitude of generation of induced plasma and ion lines from the initial interaction height, whereas for O-mode heating the region of interaction descended. The observations are consistent with the coexistence of the electron acceleration along and across the geomagnetic field at fH<5fce, while only very strong electron acceleration along the magnetic field was observed at fH≥5fce. Peer-reviewed Post-print |
format |
Article in Journal/Newspaper |
author |
Blagoveshchenskaya, N. F. Borisova, T. D. Kalishin, A. S. Yeoman, Timothy K. Häggström, I. |
spellingShingle |
Blagoveshchenskaya, N. F. Borisova, T. D. Kalishin, A. S. Yeoman, Timothy K. Häggström, I. First observations of electron gyro-harmonic effects under X-mode HF pumping the high latitude ionospheric F-region |
author_facet |
Blagoveshchenskaya, N. F. Borisova, T. D. Kalishin, A. S. Yeoman, Timothy K. Häggström, I. |
author_sort |
Blagoveshchenskaya, N. F. |
title |
First observations of electron gyro-harmonic effects under X-mode HF pumping the high latitude ionospheric F-region |
title_short |
First observations of electron gyro-harmonic effects under X-mode HF pumping the high latitude ionospheric F-region |
title_full |
First observations of electron gyro-harmonic effects under X-mode HF pumping the high latitude ionospheric F-region |
title_fullStr |
First observations of electron gyro-harmonic effects under X-mode HF pumping the high latitude ionospheric F-region |
title_full_unstemmed |
First observations of electron gyro-harmonic effects under X-mode HF pumping the high latitude ionospheric F-region |
title_sort |
first observations of electron gyro-harmonic effects under x-mode hf pumping the high latitude ionospheric f-region |
publisher |
Elsevier |
publishDate |
2017 |
url |
http://www.sciencedirect.com/science/article/pii/S1364682617300834 http://hdl.handle.net/2381/39604 https://doi.org/10.1016/j.jastp.2017.02.003 |
geographic |
Tromsø |
geographic_facet |
Tromsø |
genre |
EISCAT Tromsø |
genre_facet |
EISCAT Tromsø |
op_relation |
Journal of Atmospheric and Solar-Terrestrial Physics, 2017, 155, pp. 36-49 1364-6826 http://www.sciencedirect.com/science/article/pii/S1364682617300834 http://hdl.handle.net/2381/39604 doi:10.1016/j.jastp.2017.02.003 |
op_rights |
Copyright © 2017, Elsevier. Deposited with reference to the publisher’s archiving policy available on the SHERPA/RoMEO website. |
op_doi |
https://doi.org/10.1016/j.jastp.2017.02.003 |
container_title |
Journal of Atmospheric and Solar-Terrestrial Physics |
container_volume |
155 |
container_start_page |
36 |
op_container_end_page |
49 |
_version_ |
1766400285831331840 |