Excitation thresholds of field-aligned irregularities and associated ionospheric hysteresis at very high latitudes observed using SPEAR-induced HF radar backscatter
On 10 October 2006 the SPEAR high power radar facility was operated in a power-stepping mode where both CUTLASS radars were detecting backscatter from the SPEAR-induced field-aligned irregularities (FAIs). The effective radiated power of SPEAR was varied from 1–10 MW. The aim of the experiment was t...
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Copernicus Publications on behalf of the European Geosciences Union (EGU)
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Online Access: | http://www.ann-geophys.net/27/2623/2009/ http://hdl.handle.net/2381/8226 https://doi.org/10.5194/angeo-27-2623-2009 |
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ftleicester:oai:lra.le.ac.uk:2381/8226 2023-05-15T16:04:45+02:00 Excitation thresholds of field-aligned irregularities and associated ionospheric hysteresis at very high latitudes observed using SPEAR-induced HF radar backscatter Wright, D. M. Dhillon, R. S. Yeoman, Tim K. Robinson, T. R. Thomas, E. C. Baddeley, L. J. Imber, S. 2010-07-14T13:47:00Z http://www.ann-geophys.net/27/2623/2009/ http://hdl.handle.net/2381/8226 https://doi.org/10.5194/angeo-27-2623-2009 en eng Copernicus Publications on behalf of the European Geosciences Union (EGU) Radio and Space Plasma Physics Annales Geophysicae, 2009, 27 (7), pp. 2623-2631. 0992-7689 http://www.ann-geophys.net/27/2623/2009/ http://hdl.handle.net/2381/8226 doi:10.5194/angeo-27-2623-2009 This paper was published as Annales Geophysicae, 2009, 27 (7), pp. 2623-2631. It is also available from http://www.ann-geophys.net/27/2623/2009/angeo-27-2623-2009.html. Doi:10.5194/angeo-27-2623-2009 Article 2010 ftleicester https://doi.org/10.5194/angeo-27-2623-2009 2019-03-22T20:14:13Z On 10 October 2006 the SPEAR high power radar facility was operated in a power-stepping mode where both CUTLASS radars were detecting backscatter from the SPEAR-induced field-aligned irregularities (FAIs). The effective radiated power of SPEAR was varied from 1–10 MW. The aim of the experiment was to investigate the power thresholds for excitation (Pt) and collapse (Pc) of artificially-induced FAIs in the ionosphere over Svalbard. It was demonstrated that FAI could be excited by a SPEAR ERP of only 1 MW, representing only 1/30th of SPEAR's total capability, and that once created the irregularities could be maintained for even lower powers. The experiment also demonstrated that the very high latitude ionosphere exhibits hysteresis, where the down-going part of the power cycle provided a higher density of irregularities than for the equivalent part of the up-going cycle. Although this second result is similar to that observed previously by CUTLASS in conjunction with the Tromsø heater, the same is not true for the equivalent incoherent scatter measurements. The EISCAT Svalbard Radar (ESR) failed to detect any hysteresis in the plasma parameters over Svalbard in stark contract with the measurements made using the Tromsø UHF. Article in Journal/Newspaper EISCAT Svalbard Tromsø University of Leicester: Leicester Research Archive (LRA) Svalbard Tromsø Annales Geophysicae 27 7 2623 2631 |
institution |
Open Polar |
collection |
University of Leicester: Leicester Research Archive (LRA) |
op_collection_id |
ftleicester |
language |
English |
description |
On 10 October 2006 the SPEAR high power radar facility was operated in a power-stepping mode where both CUTLASS radars were detecting backscatter from the SPEAR-induced field-aligned irregularities (FAIs). The effective radiated power of SPEAR was varied from 1–10 MW. The aim of the experiment was to investigate the power thresholds for excitation (Pt) and collapse (Pc) of artificially-induced FAIs in the ionosphere over Svalbard. It was demonstrated that FAI could be excited by a SPEAR ERP of only 1 MW, representing only 1/30th of SPEAR's total capability, and that once created the irregularities could be maintained for even lower powers. The experiment also demonstrated that the very high latitude ionosphere exhibits hysteresis, where the down-going part of the power cycle provided a higher density of irregularities than for the equivalent part of the up-going cycle. Although this second result is similar to that observed previously by CUTLASS in conjunction with the Tromsø heater, the same is not true for the equivalent incoherent scatter measurements. The EISCAT Svalbard Radar (ESR) failed to detect any hysteresis in the plasma parameters over Svalbard in stark contract with the measurements made using the Tromsø UHF. |
format |
Article in Journal/Newspaper |
author |
Wright, D. M. Dhillon, R. S. Yeoman, Tim K. Robinson, T. R. Thomas, E. C. Baddeley, L. J. Imber, S. |
spellingShingle |
Wright, D. M. Dhillon, R. S. Yeoman, Tim K. Robinson, T. R. Thomas, E. C. Baddeley, L. J. Imber, S. Excitation thresholds of field-aligned irregularities and associated ionospheric hysteresis at very high latitudes observed using SPEAR-induced HF radar backscatter |
author_facet |
Wright, D. M. Dhillon, R. S. Yeoman, Tim K. Robinson, T. R. Thomas, E. C. Baddeley, L. J. Imber, S. |
author_sort |
Wright, D. M. |
title |
Excitation thresholds of field-aligned irregularities and associated ionospheric hysteresis at very high latitudes observed using SPEAR-induced HF radar backscatter |
title_short |
Excitation thresholds of field-aligned irregularities and associated ionospheric hysteresis at very high latitudes observed using SPEAR-induced HF radar backscatter |
title_full |
Excitation thresholds of field-aligned irregularities and associated ionospheric hysteresis at very high latitudes observed using SPEAR-induced HF radar backscatter |
title_fullStr |
Excitation thresholds of field-aligned irregularities and associated ionospheric hysteresis at very high latitudes observed using SPEAR-induced HF radar backscatter |
title_full_unstemmed |
Excitation thresholds of field-aligned irregularities and associated ionospheric hysteresis at very high latitudes observed using SPEAR-induced HF radar backscatter |
title_sort |
excitation thresholds of field-aligned irregularities and associated ionospheric hysteresis at very high latitudes observed using spear-induced hf radar backscatter |
publisher |
Copernicus Publications on behalf of the European Geosciences Union (EGU) |
publishDate |
2010 |
url |
http://www.ann-geophys.net/27/2623/2009/ http://hdl.handle.net/2381/8226 https://doi.org/10.5194/angeo-27-2623-2009 |
geographic |
Svalbard Tromsø |
geographic_facet |
Svalbard Tromsø |
genre |
EISCAT Svalbard Tromsø |
genre_facet |
EISCAT Svalbard Tromsø |
op_relation |
Radio and Space Plasma Physics Annales Geophysicae, 2009, 27 (7), pp. 2623-2631. 0992-7689 http://www.ann-geophys.net/27/2623/2009/ http://hdl.handle.net/2381/8226 doi:10.5194/angeo-27-2623-2009 |
op_rights |
This paper was published as Annales Geophysicae, 2009, 27 (7), pp. 2623-2631. It is also available from http://www.ann-geophys.net/27/2623/2009/angeo-27-2623-2009.html. Doi:10.5194/angeo-27-2623-2009 |
op_doi |
https://doi.org/10.5194/angeo-27-2623-2009 |
container_title |
Annales Geophysicae |
container_volume |
27 |
container_issue |
7 |
container_start_page |
2623 |
op_container_end_page |
2631 |
_version_ |
1766400375402790912 |