Ion Gyro‐Harmonic Structures in Stimulated Emission Excited by X‐Mode High Power HF Radio Waves at EISCAT
The distinctive features of the ion gyro-harmonic discrete structures in the narrowband stimulated electromagnetic emission (NSEE) spectra (within ±1 kHz of the heater frequency), excited by an extraordinary (X-mode) polarized high frequency (HF) pump wave in the F-region of the high latitude ionosp...
Main Authors: | , , , |
---|---|
Format: | Article in Journal/Newspaper |
Language: | unknown |
Published: |
2021
|
Subjects: | |
Online Access: | https://figshare.com/articles/journal_contribution/Ion_Gyro_Harmonic_Structures_in_Stimulated_Emission_Excited_by_X_Mode_High_Power_HF_Radio_Waves_at_EISCAT/16595546 |
id |
ftleicesterunfig:oai:figshare.com:article/16595546 |
---|---|
record_format |
openpolar |
spelling |
ftleicesterunfig:oai:figshare.com:article/16595546 2024-09-15T18:04:28+00:00 Ion Gyro‐Harmonic Structures in Stimulated Emission Excited by X‐Mode High Power HF Radio Waves at EISCAT AS Kalishin NF Blagoveshchenskaya TD Borisova TK Yeoman 2021-07-29T00:00:00Z https://figshare.com/articles/journal_contribution/Ion_Gyro_Harmonic_Structures_in_Stimulated_Emission_Excited_by_X_Mode_High_Power_HF_Radio_Waves_at_EISCAT/16595546 unknown 2381/16595546.v1 https://figshare.com/articles/journal_contribution/Ion_Gyro_Harmonic_Structures_in_Stimulated_Emission_Excited_by_X_Mode_High_Power_HF_Radio_Waves_at_EISCAT/16595546 All Rights Reserved high power HF radio waves high latitude ionosphere stimulated electromagnetic emission EISCAT Text Journal contribution 2021 ftleicesterunfig 2024-07-22T04:15:17Z The distinctive features of the ion gyro-harmonic discrete structures in the narrowband stimulated electromagnetic emission (NSEE) spectra (within ±1 kHz of the heater frequency), excited by an extraordinary (X-mode) polarized high frequency (HF) pump wave in the F-region of the high latitude ionosphere, are reported. Results were obtained from three sets of experiments at the EISCAT (European incoherent Scatter) HF Heating facility at pump frequencies of 5.423, 6.77 and 7.953 MHz, which are below the fourth, fifth, and sixth electron gyro-harmonics. High power HF radio waves were radiated in the magnetic field-aligned direction with an effective radiated power of 238–740 MW. Discrete spectral features, ordered by the ion gyro frequency (for O+ ions), were recorded at a large distance (1,200 km) away from the Heating facility. Up to 10 downshifted discrete ion gyro-harmonic structures paired with the upshifted spectral components (Stokes and anti-Stokes modes) in the NSEE spectra have been excited in the course of these experiments. It was found that preconditioning effects have a significant impact on the temporal evolution of the discrete spectral structures. The ion gyro-harmonic structures coexisted with field-aligned artificial irregularities (FAIs). Comparing the NSEE and EISCAT incoherent scatter radar observational results, it was concluded that the electron accelerations along and across the geomagnetic field coexist during X-mode heating. The magnetized stimulated Brillouin scatter and stimulated ion Bernstein scatter are discussed as relevant processes for the observed multiple down- and upshifted ion gyro-harmonic structures in the NSEE spectra. Plain Language Summary Experiments in the Earth's ionosphere (part of the upper atmosphere) using high power high frequency (HF, or shortwave) radio waves may be used to study a wide variety of fundamental phenomena. We discuss recent advances in observations of stimulated radio emissions generated by a powerful HF radio transmitter at the European incoherent ... Article in Journal/Newspaper EISCAT University of Leicester: Figshare |
institution |
Open Polar |
collection |
University of Leicester: Figshare |
op_collection_id |
ftleicesterunfig |
language |
unknown |
topic |
high power HF radio waves high latitude ionosphere stimulated electromagnetic emission EISCAT |
spellingShingle |
high power HF radio waves high latitude ionosphere stimulated electromagnetic emission EISCAT AS Kalishin NF Blagoveshchenskaya TD Borisova TK Yeoman Ion Gyro‐Harmonic Structures in Stimulated Emission Excited by X‐Mode High Power HF Radio Waves at EISCAT |
topic_facet |
high power HF radio waves high latitude ionosphere stimulated electromagnetic emission EISCAT |
description |
The distinctive features of the ion gyro-harmonic discrete structures in the narrowband stimulated electromagnetic emission (NSEE) spectra (within ±1 kHz of the heater frequency), excited by an extraordinary (X-mode) polarized high frequency (HF) pump wave in the F-region of the high latitude ionosphere, are reported. Results were obtained from three sets of experiments at the EISCAT (European incoherent Scatter) HF Heating facility at pump frequencies of 5.423, 6.77 and 7.953 MHz, which are below the fourth, fifth, and sixth electron gyro-harmonics. High power HF radio waves were radiated in the magnetic field-aligned direction with an effective radiated power of 238–740 MW. Discrete spectral features, ordered by the ion gyro frequency (for O+ ions), were recorded at a large distance (1,200 km) away from the Heating facility. Up to 10 downshifted discrete ion gyro-harmonic structures paired with the upshifted spectral components (Stokes and anti-Stokes modes) in the NSEE spectra have been excited in the course of these experiments. It was found that preconditioning effects have a significant impact on the temporal evolution of the discrete spectral structures. The ion gyro-harmonic structures coexisted with field-aligned artificial irregularities (FAIs). Comparing the NSEE and EISCAT incoherent scatter radar observational results, it was concluded that the electron accelerations along and across the geomagnetic field coexist during X-mode heating. The magnetized stimulated Brillouin scatter and stimulated ion Bernstein scatter are discussed as relevant processes for the observed multiple down- and upshifted ion gyro-harmonic structures in the NSEE spectra. Plain Language Summary Experiments in the Earth's ionosphere (part of the upper atmosphere) using high power high frequency (HF, or shortwave) radio waves may be used to study a wide variety of fundamental phenomena. We discuss recent advances in observations of stimulated radio emissions generated by a powerful HF radio transmitter at the European incoherent ... |
format |
Article in Journal/Newspaper |
author |
AS Kalishin NF Blagoveshchenskaya TD Borisova TK Yeoman |
author_facet |
AS Kalishin NF Blagoveshchenskaya TD Borisova TK Yeoman |
author_sort |
AS Kalishin |
title |
Ion Gyro‐Harmonic Structures in Stimulated Emission Excited by X‐Mode High Power HF Radio Waves at EISCAT |
title_short |
Ion Gyro‐Harmonic Structures in Stimulated Emission Excited by X‐Mode High Power HF Radio Waves at EISCAT |
title_full |
Ion Gyro‐Harmonic Structures in Stimulated Emission Excited by X‐Mode High Power HF Radio Waves at EISCAT |
title_fullStr |
Ion Gyro‐Harmonic Structures in Stimulated Emission Excited by X‐Mode High Power HF Radio Waves at EISCAT |
title_full_unstemmed |
Ion Gyro‐Harmonic Structures in Stimulated Emission Excited by X‐Mode High Power HF Radio Waves at EISCAT |
title_sort |
ion gyro‐harmonic structures in stimulated emission excited by x‐mode high power hf radio waves at eiscat |
publishDate |
2021 |
url |
https://figshare.com/articles/journal_contribution/Ion_Gyro_Harmonic_Structures_in_Stimulated_Emission_Excited_by_X_Mode_High_Power_HF_Radio_Waves_at_EISCAT/16595546 |
genre |
EISCAT |
genre_facet |
EISCAT |
op_relation |
2381/16595546.v1 https://figshare.com/articles/journal_contribution/Ion_Gyro_Harmonic_Structures_in_Stimulated_Emission_Excited_by_X_Mode_High_Power_HF_Radio_Waves_at_EISCAT/16595546 |
op_rights |
All Rights Reserved |
_version_ |
1810441972264992768 |