Artificial Ducts Created via High-Power HF Radio Waves at EISCAT
Ducts (field-aligned plasma density enhancements) provide a link into the magnetosphere and can guide whistler waves. Inside ducts, wave-particle interactions occur efficiently; therefore, their presence contributes to the removal of energetic particles from the magnetosphere. We present experimenta...
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ftmdpi:oai:mdpi.com:/2072-4292/15/9/2300/ 2023-08-20T04:06:14+02:00 Artificial Ducts Created via High-Power HF Radio Waves at EISCAT Nataly F. Blagoveshchenskaya Tatiana D. Borisova Alexey S. Kalishin Ivan M. Egorov agris 2023-04-27 application/pdf https://doi.org/10.3390/rs15092300 EN eng Multidisciplinary Digital Publishing Institute Atmospheric Remote Sensing https://dx.doi.org/10.3390/rs15092300 https://creativecommons.org/licenses/by/4.0/ Remote Sensing; Volume 15; Issue 9; Pages: 2300 high-latitude ionosphere duct electron density HF pump wave incoherent scatter radar polarization artificial field-aligned irregularities EISCAT Text 2023 ftmdpi https://doi.org/10.3390/rs15092300 2023-08-01T09:52:02Z Ducts (field-aligned plasma density enhancements) provide a link into the magnetosphere and can guide whistler waves. Inside ducts, wave-particle interactions occur efficiently; therefore, their presence contributes to the removal of energetic particles from the magnetosphere. We present experimental results concerning the characteristics, behavior, and excitation thresholds of ducts induced by extraordinary (X-mode) polarized high-power HF radio waves emitted towards the magnetic zenith (MZ) into the upper ionosphere at EISCAT (European Incoherent SCATter). The features and behavior of ducts were diagnosed by the EISCAT incoherent scatter radar (ISR) at Tromsø and the CUTLASS (SuperDARN) Finland radar at Hankasalmi. The state of the ionosphere was monitored by the Dynasonde in Tromsø. It was found that the electron density Ne enhancements inside ducts were of 50–80% above the background Ne values and their transverse size (normal to the magnetic flux tube) corresponded to about 3–4° in the north–south direction. They were generated during magnetically quiet periods and extended from ~300 to 320 km up to the upper altitude limit of the EISCAT radar measurements (600–700 km), when heater frequencies were both below and above the critical frequency of the F2 layer (fH ≤ foF2 and fH > foF2), regardless of whether HF-induced plasma and ion lines were generated or not. Comparing the O-/X-mode effects from the EISCAT radar observations, it was shown that the creation of the strong Ne ducts is a typical characteristic of the X-mode pulses. As a rule, electron density enhancements were not observed during O-mode pulses. A plausible mechanism for the creation of X-mode artificial ducts is discussed. Text EISCAT Tromsø MDPI Open Access Publishing Tromsø Remote Sensing 15 9 2300 |
institution |
Open Polar |
collection |
MDPI Open Access Publishing |
op_collection_id |
ftmdpi |
language |
English |
topic |
high-latitude ionosphere duct electron density HF pump wave incoherent scatter radar polarization artificial field-aligned irregularities EISCAT |
spellingShingle |
high-latitude ionosphere duct electron density HF pump wave incoherent scatter radar polarization artificial field-aligned irregularities EISCAT Nataly F. Blagoveshchenskaya Tatiana D. Borisova Alexey S. Kalishin Ivan M. Egorov Artificial Ducts Created via High-Power HF Radio Waves at EISCAT |
topic_facet |
high-latitude ionosphere duct electron density HF pump wave incoherent scatter radar polarization artificial field-aligned irregularities EISCAT |
description |
Ducts (field-aligned plasma density enhancements) provide a link into the magnetosphere and can guide whistler waves. Inside ducts, wave-particle interactions occur efficiently; therefore, their presence contributes to the removal of energetic particles from the magnetosphere. We present experimental results concerning the characteristics, behavior, and excitation thresholds of ducts induced by extraordinary (X-mode) polarized high-power HF radio waves emitted towards the magnetic zenith (MZ) into the upper ionosphere at EISCAT (European Incoherent SCATter). The features and behavior of ducts were diagnosed by the EISCAT incoherent scatter radar (ISR) at Tromsø and the CUTLASS (SuperDARN) Finland radar at Hankasalmi. The state of the ionosphere was monitored by the Dynasonde in Tromsø. It was found that the electron density Ne enhancements inside ducts were of 50–80% above the background Ne values and their transverse size (normal to the magnetic flux tube) corresponded to about 3–4° in the north–south direction. They were generated during magnetically quiet periods and extended from ~300 to 320 km up to the upper altitude limit of the EISCAT radar measurements (600–700 km), when heater frequencies were both below and above the critical frequency of the F2 layer (fH ≤ foF2 and fH > foF2), regardless of whether HF-induced plasma and ion lines were generated or not. Comparing the O-/X-mode effects from the EISCAT radar observations, it was shown that the creation of the strong Ne ducts is a typical characteristic of the X-mode pulses. As a rule, electron density enhancements were not observed during O-mode pulses. A plausible mechanism for the creation of X-mode artificial ducts is discussed. |
format |
Text |
author |
Nataly F. Blagoveshchenskaya Tatiana D. Borisova Alexey S. Kalishin Ivan M. Egorov |
author_facet |
Nataly F. Blagoveshchenskaya Tatiana D. Borisova Alexey S. Kalishin Ivan M. Egorov |
author_sort |
Nataly F. Blagoveshchenskaya |
title |
Artificial Ducts Created via High-Power HF Radio Waves at EISCAT |
title_short |
Artificial Ducts Created via High-Power HF Radio Waves at EISCAT |
title_full |
Artificial Ducts Created via High-Power HF Radio Waves at EISCAT |
title_fullStr |
Artificial Ducts Created via High-Power HF Radio Waves at EISCAT |
title_full_unstemmed |
Artificial Ducts Created via High-Power HF Radio Waves at EISCAT |
title_sort |
artificial ducts created via high-power hf radio waves at eiscat |
publisher |
Multidisciplinary Digital Publishing Institute |
publishDate |
2023 |
url |
https://doi.org/10.3390/rs15092300 |
op_coverage |
agris |
geographic |
Tromsø |
geographic_facet |
Tromsø |
genre |
EISCAT Tromsø |
genre_facet |
EISCAT Tromsø |
op_source |
Remote Sensing; Volume 15; Issue 9; Pages: 2300 |
op_relation |
Atmospheric Remote Sensing https://dx.doi.org/10.3390/rs15092300 |
op_rights |
https://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.3390/rs15092300 |
container_title |
Remote Sensing |
container_volume |
15 |
container_issue |
9 |
container_start_page |
2300 |
_version_ |
1774717208935530496 |