Letter to the Editor : First direct observations of the reduced striations at pump frequencies close to the electron gyroharmonics
It is well known that the ionospheric plasma response to high-power HF radio waves changes drastically as the heater frequency approaches harmonics of the electron gyrofrequency. These include changes in the spectrum of the stimulated electromagnetic emission, reduction in the anomalous absorption o...
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ftdoajarticles:oai:doaj.org/article:1573214aeb734585914fd15fb2138a6a 2023-05-15T16:04:33+02:00 Letter to the Editor : First direct observations of the reduced striations at pump frequencies close to the electron gyroharmonics F. Honary T. R. Robinson D. M. Wright A. J. Stocker M. T. Rietveld I. McCrea 1999-09-01T00:00:00Z https://doi.org/10.1007/s00585-999-1235-6 https://doaj.org/article/1573214aeb734585914fd15fb2138a6a EN eng Copernicus Publications https://www.ann-geophys.net/17/1235/1999/angeo-17-1235-1999.pdf https://doaj.org/toc/0992-7689 https://doaj.org/toc/1432-0576 doi:10.1007/s00585-999-1235-6 0992-7689 1432-0576 https://doaj.org/article/1573214aeb734585914fd15fb2138a6a Annales Geophysicae, Vol 17, Pp 1235-1238 (1999) Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 article 1999 ftdoajarticles https://doi.org/10.1007/s00585-999-1235-6 2022-12-31T16:24:29Z It is well known that the ionospheric plasma response to high-power HF radio waves changes drastically as the heater frequency approaches harmonics of the electron gyrofrequency. These include changes in the spectrum of the stimulated electromagnetic emission, reduction in the anomalous absorption of low-power diagnostic waves propagating through the heated volume, and reduction in the large scale F-region heating. Theoretical models as well as previous experimental evidence point towards the absence of small-scale field-aligned plasma density irregularities at pump frequencies close to electron gyroharmonics as the main cause of these changes. Results presented in this paper are the first direct observations of the reduced striations at the 3rd gyroharmonic made by the CUTLASS radar. In addition, simultaneous EISCAT observations have revealed that the "enhanced ion-line" usually present in the EISCAT ion-line spectrum during the first few seconds after heater switch on, persisted at varying strengths while the heater was transmitting at frequencies close to the 3rd electron gyroharmonics. Key words. Ionosphere (active experiments; ionospheric irregularities) · Radio science (ionospheric physics) Article in Journal/Newspaper EISCAT Directory of Open Access Journals: DOAJ Articles Annales Geophysicae 17 9 1235 1238 |
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Directory of Open Access Journals: DOAJ Articles |
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English |
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Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 |
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Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 F. Honary T. R. Robinson D. M. Wright A. J. Stocker M. T. Rietveld I. McCrea Letter to the Editor : First direct observations of the reduced striations at pump frequencies close to the electron gyroharmonics |
topic_facet |
Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 |
description |
It is well known that the ionospheric plasma response to high-power HF radio waves changes drastically as the heater frequency approaches harmonics of the electron gyrofrequency. These include changes in the spectrum of the stimulated electromagnetic emission, reduction in the anomalous absorption of low-power diagnostic waves propagating through the heated volume, and reduction in the large scale F-region heating. Theoretical models as well as previous experimental evidence point towards the absence of small-scale field-aligned plasma density irregularities at pump frequencies close to electron gyroharmonics as the main cause of these changes. Results presented in this paper are the first direct observations of the reduced striations at the 3rd gyroharmonic made by the CUTLASS radar. In addition, simultaneous EISCAT observations have revealed that the "enhanced ion-line" usually present in the EISCAT ion-line spectrum during the first few seconds after heater switch on, persisted at varying strengths while the heater was transmitting at frequencies close to the 3rd electron gyroharmonics. Key words. Ionosphere (active experiments; ionospheric irregularities) · Radio science (ionospheric physics) |
format |
Article in Journal/Newspaper |
author |
F. Honary T. R. Robinson D. M. Wright A. J. Stocker M. T. Rietveld I. McCrea |
author_facet |
F. Honary T. R. Robinson D. M. Wright A. J. Stocker M. T. Rietveld I. McCrea |
author_sort |
F. Honary |
title |
Letter to the Editor : First direct observations of the reduced striations at pump frequencies close to the electron gyroharmonics |
title_short |
Letter to the Editor : First direct observations of the reduced striations at pump frequencies close to the electron gyroharmonics |
title_full |
Letter to the Editor : First direct observations of the reduced striations at pump frequencies close to the electron gyroharmonics |
title_fullStr |
Letter to the Editor : First direct observations of the reduced striations at pump frequencies close to the electron gyroharmonics |
title_full_unstemmed |
Letter to the Editor : First direct observations of the reduced striations at pump frequencies close to the electron gyroharmonics |
title_sort |
letter to the editor : first direct observations of the reduced striations at pump frequencies close to the electron gyroharmonics |
publisher |
Copernicus Publications |
publishDate |
1999 |
url |
https://doi.org/10.1007/s00585-999-1235-6 https://doaj.org/article/1573214aeb734585914fd15fb2138a6a |
genre |
EISCAT |
genre_facet |
EISCAT |
op_source |
Annales Geophysicae, Vol 17, Pp 1235-1238 (1999) |
op_relation |
https://www.ann-geophys.net/17/1235/1999/angeo-17-1235-1999.pdf https://doaj.org/toc/0992-7689 https://doaj.org/toc/1432-0576 doi:10.1007/s00585-999-1235-6 0992-7689 1432-0576 https://doaj.org/article/1573214aeb734585914fd15fb2138a6a |
op_doi |
https://doi.org/10.1007/s00585-999-1235-6 |
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Annales Geophysicae |
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17 |
container_issue |
9 |
container_start_page |
1235 |
op_container_end_page |
1238 |
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