Geophysical phenomena during an ionospheric modification experiment at Tromsø, Norway
International audience We present an analysis of phenomena observed by HF distance-diagnostic tools located in St. Petersburg combined with multi-instrument observation at Tromsø in the HF modified ionosphere during a magnetospheric substorm. The observed phenomena that occurred during the Tromsø he...
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ftccsdartic:oai:HAL:hal-00316449v1 2023-11-12T04:27:29+01:00 Geophysical phenomena during an ionospheric modification experiment at Tromsø, Norway Blagoveshchenskaya, N. F. Kornienko, V. A. Petlenko, A. V. Brekke, A. Rietveld, M. T. Arctic and Antarctic Research Institute (AARI) Russian Federal Service for Hydrometeorology and Environmental Monitoring (Roshydromet) The Auroral Observatory University of Tromsø (UiT) EISCAT Scientific Association Norway 1998 https://hal.science/hal-00316449 https://hal.science/hal-00316449/document https://hal.science/hal-00316449/file/angeo-16-1212-1998.pdf en eng HAL CCSD European Geosciences Union hal-00316449 https://hal.science/hal-00316449 https://hal.science/hal-00316449/document https://hal.science/hal-00316449/file/angeo-16-1212-1998.pdf info:eu-repo/semantics/OpenAccess ISSN: 0992-7689 EISSN: 1432-0576 Annales Geophysicae https://hal.science/hal-00316449 Annales Geophysicae, 1998, 16 (10), pp.1212-1225 [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences info:eu-repo/semantics/article Journal articles 1998 ftccsdartic 2023-10-21T23:08:27Z International audience We present an analysis of phenomena observed by HF distance-diagnostic tools located in St. Petersburg combined with multi-instrument observation at Tromsø in the HF modified ionosphere during a magnetospheric substorm. The observed phenomena that occurred during the Tromsø heating experiment in the nightside auroral E s region of the ionosphere depend on the phase of substorm. The heating excited small-scale field-aligned irregularities in the E region responsible for field-aligned scattering of diagnostic HF waves. The equipment used in the experiment was sensitive to electron density irregularities with wavelengths 12?15 m across the geomagnetic field lines. Analysis of the Doppler measurement data shows the appearance of quasiperiodic variations with a Doppler frequency shift, f d and periods about 100?120 s during the heating cycle coinciding in time with the first substorm activation and initiation of the upward field-aligned currents. A relationship between wave variations in f d and magnetic pulsations in the Y -component of the geomagnetic field at Tromsø was detected. The analysis of the magnetic field variations from the IMAGE magnetometer stations shows that ULF waves occurred, not only at Tromsø, but in the adjacent area bounded by geographical latitudes from 70.5° to 68° and longitudes from 16° to 27°. It is suggested that the ULF observed can result from superposition of the natural and heater-induced ULF waves. During the substorm expansion a strong stimulated electromagnetic emission (SEE) at the third harmonic of the downshifted maximum frequency was found. It is believed that SEE is accompanied by excitation of the VLF waves penetrating into magnetosphere and stimulating the precipitation of the energetic electrons (10?40 keV) of about 1-min duration. This is due to a cyclotron resonant interaction of natural precipitating electrons (1?10 keV) with heater-induced whistler waves in the magnetosphere. It is reasonable to suppose that a new substorm activation, exactly ... Article in Journal/Newspaper Tromsø Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) Norway Tromsø The ''Y'' ENVELOPE(-112.453,-112.453,57.591,57.591) |
institution |
Open Polar |
collection |
Archive ouverte HAL (Hyper Article en Ligne, CCSD - Centre pour la Communication Scientifique Directe) |
op_collection_id |
ftccsdartic |
language |
English |
topic |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
spellingShingle |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences Blagoveshchenskaya, N. F. Kornienko, V. A. Petlenko, A. V. Brekke, A. Rietveld, M. T. Geophysical phenomena during an ionospheric modification experiment at Tromsø, Norway |
topic_facet |
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere [SDU.STU]Sciences of the Universe [physics]/Earth Sciences |
description |
International audience We present an analysis of phenomena observed by HF distance-diagnostic tools located in St. Petersburg combined with multi-instrument observation at Tromsø in the HF modified ionosphere during a magnetospheric substorm. The observed phenomena that occurred during the Tromsø heating experiment in the nightside auroral E s region of the ionosphere depend on the phase of substorm. The heating excited small-scale field-aligned irregularities in the E region responsible for field-aligned scattering of diagnostic HF waves. The equipment used in the experiment was sensitive to electron density irregularities with wavelengths 12?15 m across the geomagnetic field lines. Analysis of the Doppler measurement data shows the appearance of quasiperiodic variations with a Doppler frequency shift, f d and periods about 100?120 s during the heating cycle coinciding in time with the first substorm activation and initiation of the upward field-aligned currents. A relationship between wave variations in f d and magnetic pulsations in the Y -component of the geomagnetic field at Tromsø was detected. The analysis of the magnetic field variations from the IMAGE magnetometer stations shows that ULF waves occurred, not only at Tromsø, but in the adjacent area bounded by geographical latitudes from 70.5° to 68° and longitudes from 16° to 27°. It is suggested that the ULF observed can result from superposition of the natural and heater-induced ULF waves. During the substorm expansion a strong stimulated electromagnetic emission (SEE) at the third harmonic of the downshifted maximum frequency was found. It is believed that SEE is accompanied by excitation of the VLF waves penetrating into magnetosphere and stimulating the precipitation of the energetic electrons (10?40 keV) of about 1-min duration. This is due to a cyclotron resonant interaction of natural precipitating electrons (1?10 keV) with heater-induced whistler waves in the magnetosphere. It is reasonable to suppose that a new substorm activation, exactly ... |
author2 |
Arctic and Antarctic Research Institute (AARI) Russian Federal Service for Hydrometeorology and Environmental Monitoring (Roshydromet) The Auroral Observatory University of Tromsø (UiT) EISCAT Scientific Association Norway |
format |
Article in Journal/Newspaper |
author |
Blagoveshchenskaya, N. F. Kornienko, V. A. Petlenko, A. V. Brekke, A. Rietveld, M. T. |
author_facet |
Blagoveshchenskaya, N. F. Kornienko, V. A. Petlenko, A. V. Brekke, A. Rietveld, M. T. |
author_sort |
Blagoveshchenskaya, N. F. |
title |
Geophysical phenomena during an ionospheric modification experiment at Tromsø, Norway |
title_short |
Geophysical phenomena during an ionospheric modification experiment at Tromsø, Norway |
title_full |
Geophysical phenomena during an ionospheric modification experiment at Tromsø, Norway |
title_fullStr |
Geophysical phenomena during an ionospheric modification experiment at Tromsø, Norway |
title_full_unstemmed |
Geophysical phenomena during an ionospheric modification experiment at Tromsø, Norway |
title_sort |
geophysical phenomena during an ionospheric modification experiment at tromsø, norway |
publisher |
HAL CCSD |
publishDate |
1998 |
url |
https://hal.science/hal-00316449 https://hal.science/hal-00316449/document https://hal.science/hal-00316449/file/angeo-16-1212-1998.pdf |
long_lat |
ENVELOPE(-112.453,-112.453,57.591,57.591) |
geographic |
Norway Tromsø The ''Y'' |
geographic_facet |
Norway Tromsø The ''Y'' |
genre |
Tromsø |
genre_facet |
Tromsø |
op_source |
ISSN: 0992-7689 EISSN: 1432-0576 Annales Geophysicae https://hal.science/hal-00316449 Annales Geophysicae, 1998, 16 (10), pp.1212-1225 |
op_relation |
hal-00316449 https://hal.science/hal-00316449 https://hal.science/hal-00316449/document https://hal.science/hal-00316449/file/angeo-16-1212-1998.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1782341071041200128 |