A quantitative analysis of the diurnal evolution of Ionospheric Alfven resonator magnetic resonance features and calculation of changing IAR parameters
Resonance features of the Ionospheric Alfvén Resonator (IAR) can be observed in pulsation magnetometer data from Sodankylä, Finland using dynamic spectra visualizations. IAR resonance features were identified on 13 of 30 days in October 1998, with resonance structures lasting for 3 or more hours ove...
Published in: | Annales Geophysicae |
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Format: | Article in Journal/Newspaper |
Language: | English |
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European Geosciences Union (EGU), Copernicus Publications,. Springer Verlag (Germany)
2009
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Online Access: | http://www.ann-geophys.net/23/1711/2005/angeo-23-1711-2005.html http://hdl.handle.net/2381/711 https://doi.org/10.5194/angeo-23-1711-2005 |
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ftleicester:oai:lra.le.ac.uk:2381/711 2023-05-15T18:20:18+02:00 A quantitative analysis of the diurnal evolution of Ionospheric Alfven resonator magnetic resonance features and calculation of changing IAR parameters Hebden, S. R. Robinson, T. R. Wright, D. M. Yeoman, Tim K. Raita, T. Bosinger, T. 2009-12-08T16:24:13Z http://www.ann-geophys.net/23/1711/2005/angeo-23-1711-2005.html http://hdl.handle.net/2381/711 https://doi.org/10.5194/angeo-23-1711-2005 en eng European Geosciences Union (EGU), Copernicus Publications,. Springer Verlag (Germany) RAE 2007 Radio and Space Plasma Physics Annales Geophysicae: Atmospheres Hydrospheres and Space Science, 2005, 23 (5), pp.1711-1721 http://www.ann-geophys.net/23/1711/2005/angeo-23-1711-2005.html http://hdl.handle.net/2381/711 doi:10.5194/angeo-23-1711-2005 Available from the publisher website at http://www.ann-geophys.net/23/1711/2005/angeo-23-1711-2005.html © Author(s) 2005. This work is distributed under the Creative Commons Attribution 3.0 License. CC-BY Ionosphere (Auroral ionosphere;Wave propagation) Radio science (Electromagnetic noise and interference) Article 2009 ftleicester https://doi.org/10.5194/angeo-23-1711-2005 2019-03-22T20:13:54Z Resonance features of the Ionospheric Alfvén Resonator (IAR) can be observed in pulsation magnetometer data from Sodankylä, Finland using dynamic spectra visualizations. IAR resonance features were identified on 13 of 30 days in October 1998, with resonance structures lasting for 3 or more hours over 10 intervals. The diurnal evolution of the harmonic features was quantified for these 10 intervals using a manual cursor-clicking technique. The resonance features displayed strong linear relationships between harmonic frequency and harmonic number for all of the time intervals studied, enabling a homogeneous cavity model for the IAR to be adopted to interpret the data. This enabled the diurnal variation of the effective size of the IAR to be obtained for each of the 10 time intervals. The average effective size was found to be 530 km, and to have an average variation of 32% over each time interval: small compared to the average variation in Alfvén velocity of 61%. Thus the diurnal variation of the harmonics is chiefly caused by the changing plasma density within the IAR due to changing insolation. This study confirms Odzimek (2004) that the dominating factor affecting the IAR eigenfrequencies is the variation in the Alfvén velocity at the F-layer ion-density peak, with the changing IAR size affecting the IAR eigenfrequencies to a smaller extent. Another IAR parameter was derived from the analysis of the IAR resonance features associated with the phase matching structure of the standing waves in the IAR. This parameter varied over the time intervals studied by 20% on average, possibly due to changing ionospheric conductivity. Article in Journal/Newspaper Sodankylä University of Leicester: Leicester Research Archive (LRA) Sodankylä ENVELOPE(26.600,26.600,67.417,67.417) Annales Geophysicae 23 5 1711 1721 |
institution |
Open Polar |
collection |
University of Leicester: Leicester Research Archive (LRA) |
op_collection_id |
ftleicester |
language |
English |
topic |
Ionosphere (Auroral ionosphere;Wave propagation) Radio science (Electromagnetic noise and interference) |
spellingShingle |
Ionosphere (Auroral ionosphere;Wave propagation) Radio science (Electromagnetic noise and interference) Hebden, S. R. Robinson, T. R. Wright, D. M. Yeoman, Tim K. Raita, T. Bosinger, T. A quantitative analysis of the diurnal evolution of Ionospheric Alfven resonator magnetic resonance features and calculation of changing IAR parameters |
topic_facet |
Ionosphere (Auroral ionosphere;Wave propagation) Radio science (Electromagnetic noise and interference) |
description |
Resonance features of the Ionospheric Alfvén Resonator (IAR) can be observed in pulsation magnetometer data from Sodankylä, Finland using dynamic spectra visualizations. IAR resonance features were identified on 13 of 30 days in October 1998, with resonance structures lasting for 3 or more hours over 10 intervals. The diurnal evolution of the harmonic features was quantified for these 10 intervals using a manual cursor-clicking technique. The resonance features displayed strong linear relationships between harmonic frequency and harmonic number for all of the time intervals studied, enabling a homogeneous cavity model for the IAR to be adopted to interpret the data. This enabled the diurnal variation of the effective size of the IAR to be obtained for each of the 10 time intervals. The average effective size was found to be 530 km, and to have an average variation of 32% over each time interval: small compared to the average variation in Alfvén velocity of 61%. Thus the diurnal variation of the harmonics is chiefly caused by the changing plasma density within the IAR due to changing insolation. This study confirms Odzimek (2004) that the dominating factor affecting the IAR eigenfrequencies is the variation in the Alfvén velocity at the F-layer ion-density peak, with the changing IAR size affecting the IAR eigenfrequencies to a smaller extent. Another IAR parameter was derived from the analysis of the IAR resonance features associated with the phase matching structure of the standing waves in the IAR. This parameter varied over the time intervals studied by 20% on average, possibly due to changing ionospheric conductivity. |
format |
Article in Journal/Newspaper |
author |
Hebden, S. R. Robinson, T. R. Wright, D. M. Yeoman, Tim K. Raita, T. Bosinger, T. |
author_facet |
Hebden, S. R. Robinson, T. R. Wright, D. M. Yeoman, Tim K. Raita, T. Bosinger, T. |
author_sort |
Hebden, S. R. |
title |
A quantitative analysis of the diurnal evolution of Ionospheric Alfven resonator magnetic resonance features and calculation of changing IAR parameters |
title_short |
A quantitative analysis of the diurnal evolution of Ionospheric Alfven resonator magnetic resonance features and calculation of changing IAR parameters |
title_full |
A quantitative analysis of the diurnal evolution of Ionospheric Alfven resonator magnetic resonance features and calculation of changing IAR parameters |
title_fullStr |
A quantitative analysis of the diurnal evolution of Ionospheric Alfven resonator magnetic resonance features and calculation of changing IAR parameters |
title_full_unstemmed |
A quantitative analysis of the diurnal evolution of Ionospheric Alfven resonator magnetic resonance features and calculation of changing IAR parameters |
title_sort |
quantitative analysis of the diurnal evolution of ionospheric alfven resonator magnetic resonance features and calculation of changing iar parameters |
publisher |
European Geosciences Union (EGU), Copernicus Publications,. Springer Verlag (Germany) |
publishDate |
2009 |
url |
http://www.ann-geophys.net/23/1711/2005/angeo-23-1711-2005.html http://hdl.handle.net/2381/711 https://doi.org/10.5194/angeo-23-1711-2005 |
long_lat |
ENVELOPE(26.600,26.600,67.417,67.417) |
geographic |
Sodankylä |
geographic_facet |
Sodankylä |
genre |
Sodankylä |
genre_facet |
Sodankylä |
op_relation |
RAE 2007 Radio and Space Plasma Physics Annales Geophysicae: Atmospheres Hydrospheres and Space Science, 2005, 23 (5), pp.1711-1721 http://www.ann-geophys.net/23/1711/2005/angeo-23-1711-2005.html http://hdl.handle.net/2381/711 doi:10.5194/angeo-23-1711-2005 |
op_rights |
Available from the publisher website at http://www.ann-geophys.net/23/1711/2005/angeo-23-1711-2005.html © Author(s) 2005. This work is distributed under the Creative Commons Attribution 3.0 License. |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.5194/angeo-23-1711-2005 |
container_title |
Annales Geophysicae |
container_volume |
23 |
container_issue |
5 |
container_start_page |
1711 |
op_container_end_page |
1721 |
_version_ |
1766197821912907776 |