ELF Sferic Occurrences in the Antarctic during a Solar Proton Event: Case Study of Occurrences at Byrd Station during the Event of 9 June 1968.
Electromagnetic waves with frequencies above the extremely-low-frequency range (ELF; frequencies in the range 5 Hz-3KHz) are susceptible to a variety of solar proton event (SPE) effects when propagating through a polar region in the earth-ionosphere waveguide. These effects appear to become less sev...
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ftdtic:ADA078923 2023-05-15T14:00:45+02:00 ELF Sferic Occurrences in the Antarctic during a Solar Proton Event: Case Study of Occurrences at Byrd Station during the Event of 9 June 1968. Fraser-Smith ,A C Helliwell,R A STANFORD UNIV CALIF STANFORD ELECTRONICS LABS 1979-09-19 text/html http://www.dtic.mil/docs/citations/ADA078923 http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA078923 en eng http://www.dtic.mil/docs/citations/ADA078923 APPROVED FOR PUBLIC RELEASE DTIC AND NTIS Atmospheric Physics Radiofrequency Wave Propagation *IONOSPHERIC PROPAGATION *EXTREMELY LOW FREQUENCY *ATMOSPHERICS POLAR REGIONS PROTONS IONIZATION ATTENUATION SOLAR ACTIVITY RADIOFREQUENCY INTERFERENCE ANTARCTIC REGIONS ELECTROMAGNETIC SUSCEPTIBILITY IONOSPHERIC DISTURBANCES POLAR CAP ABSORPTION SOLAR COSMIC RAYS D REGION Seafarer project Sanguine project Solar proton events PE62710H WU49 Text 1979 ftdtic 2016-02-20T17:25:41Z Electromagnetic waves with frequencies above the extremely-low-frequency range (ELF; frequencies in the range 5 Hz-3KHz) are susceptible to a variety of solar proton event (SPE) effects when propagating through a polar region in the earth-ionosphere waveguide. These effects appear to become less severe as the frequency of the waves becomes smaller and approaches the ELF range. Although measurements have been lacking, it would be expected that ELF wave propagation through the polar regions would be comparatively stable. To investigate polar ELF wave propagation during an SPE, we have carried out a series of measurements of the properties of ELF sferics (75 Hz) at a polar location (Byrd Station, Antarctica) during a moderately-large SPE. These measurements suggest that an SPE can significantly alter the characteristics of ELF signals propagating through the polar regions; during the first 24 hours of the SPE there was a reduction of about 50% in the median amplitudes of the sferics, compared with their amplitudes before the SPE, and there were substantial changes in their rates of occurrence. Text Antarc* Antarctic Antarctica Defense Technical Information Center: DTIC Technical Reports database Antarctic Byrd Byrd Station ENVELOPE(-119.533,-119.533,-80.017,-80.017) The Antarctic |
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Open Polar |
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Defense Technical Information Center: DTIC Technical Reports database |
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ftdtic |
language |
English |
topic |
Atmospheric Physics Radiofrequency Wave Propagation *IONOSPHERIC PROPAGATION *EXTREMELY LOW FREQUENCY *ATMOSPHERICS POLAR REGIONS PROTONS IONIZATION ATTENUATION SOLAR ACTIVITY RADIOFREQUENCY INTERFERENCE ANTARCTIC REGIONS ELECTROMAGNETIC SUSCEPTIBILITY IONOSPHERIC DISTURBANCES POLAR CAP ABSORPTION SOLAR COSMIC RAYS D REGION Seafarer project Sanguine project Solar proton events PE62710H WU49 |
spellingShingle |
Atmospheric Physics Radiofrequency Wave Propagation *IONOSPHERIC PROPAGATION *EXTREMELY LOW FREQUENCY *ATMOSPHERICS POLAR REGIONS PROTONS IONIZATION ATTENUATION SOLAR ACTIVITY RADIOFREQUENCY INTERFERENCE ANTARCTIC REGIONS ELECTROMAGNETIC SUSCEPTIBILITY IONOSPHERIC DISTURBANCES POLAR CAP ABSORPTION SOLAR COSMIC RAYS D REGION Seafarer project Sanguine project Solar proton events PE62710H WU49 Fraser-Smith ,A C Helliwell,R A ELF Sferic Occurrences in the Antarctic during a Solar Proton Event: Case Study of Occurrences at Byrd Station during the Event of 9 June 1968. |
topic_facet |
Atmospheric Physics Radiofrequency Wave Propagation *IONOSPHERIC PROPAGATION *EXTREMELY LOW FREQUENCY *ATMOSPHERICS POLAR REGIONS PROTONS IONIZATION ATTENUATION SOLAR ACTIVITY RADIOFREQUENCY INTERFERENCE ANTARCTIC REGIONS ELECTROMAGNETIC SUSCEPTIBILITY IONOSPHERIC DISTURBANCES POLAR CAP ABSORPTION SOLAR COSMIC RAYS D REGION Seafarer project Sanguine project Solar proton events PE62710H WU49 |
description |
Electromagnetic waves with frequencies above the extremely-low-frequency range (ELF; frequencies in the range 5 Hz-3KHz) are susceptible to a variety of solar proton event (SPE) effects when propagating through a polar region in the earth-ionosphere waveguide. These effects appear to become less severe as the frequency of the waves becomes smaller and approaches the ELF range. Although measurements have been lacking, it would be expected that ELF wave propagation through the polar regions would be comparatively stable. To investigate polar ELF wave propagation during an SPE, we have carried out a series of measurements of the properties of ELF sferics (75 Hz) at a polar location (Byrd Station, Antarctica) during a moderately-large SPE. These measurements suggest that an SPE can significantly alter the characteristics of ELF signals propagating through the polar regions; during the first 24 hours of the SPE there was a reduction of about 50% in the median amplitudes of the sferics, compared with their amplitudes before the SPE, and there were substantial changes in their rates of occurrence. |
author2 |
STANFORD UNIV CALIF STANFORD ELECTRONICS LABS |
format |
Text |
author |
Fraser-Smith ,A C Helliwell,R A |
author_facet |
Fraser-Smith ,A C Helliwell,R A |
author_sort |
Fraser-Smith ,A C |
title |
ELF Sferic Occurrences in the Antarctic during a Solar Proton Event: Case Study of Occurrences at Byrd Station during the Event of 9 June 1968. |
title_short |
ELF Sferic Occurrences in the Antarctic during a Solar Proton Event: Case Study of Occurrences at Byrd Station during the Event of 9 June 1968. |
title_full |
ELF Sferic Occurrences in the Antarctic during a Solar Proton Event: Case Study of Occurrences at Byrd Station during the Event of 9 June 1968. |
title_fullStr |
ELF Sferic Occurrences in the Antarctic during a Solar Proton Event: Case Study of Occurrences at Byrd Station during the Event of 9 June 1968. |
title_full_unstemmed |
ELF Sferic Occurrences in the Antarctic during a Solar Proton Event: Case Study of Occurrences at Byrd Station during the Event of 9 June 1968. |
title_sort |
elf sferic occurrences in the antarctic during a solar proton event: case study of occurrences at byrd station during the event of 9 june 1968. |
publishDate |
1979 |
url |
http://www.dtic.mil/docs/citations/ADA078923 http://oai.dtic.mil/oai/oai?&verb=getRecord&metadataPrefix=html&identifier=ADA078923 |
long_lat |
ENVELOPE(-119.533,-119.533,-80.017,-80.017) |
geographic |
Antarctic Byrd Byrd Station The Antarctic |
geographic_facet |
Antarctic Byrd Byrd Station The Antarctic |
genre |
Antarc* Antarctic Antarctica |
genre_facet |
Antarc* Antarctic Antarctica |
op_source |
DTIC AND NTIS |
op_relation |
http://www.dtic.mil/docs/citations/ADA078923 |
op_rights |
APPROVED FOR PUBLIC RELEASE |
_version_ |
1766270094577500160 |