A study of quasi-periodic ELF-VLF emissions at three Antarctic stations: evidence for off-equatorial generation?
The spatial extent and temporal behaviour of quasi-periodic (QP) intensity modulations of 0.5-2 kHz ELF-VLF signals were investigated in a comparative study of data collected at the Antarctic stations of South Pole (L=14), Halley (L=4), and Siple (L=4). Frequently, the waveforms of ELF-VLF signals s...
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ftnerc:oai:nora.nerc.ac.uk:516689 2023-05-15T13:49:34+02:00 A study of quasi-periodic ELF-VLF emissions at three Antarctic stations: evidence for off-equatorial generation? Morrison, K. Engebretson, M. J. Beck, J. R. Johnson, J. E. Arnoldy, R. L. Cahill, L. J. Carpenter, D. L. Gallani, M. 1994-02 http://nora.nerc.ac.uk/id/eprint/516689/ https://doi.org/10.1007/s00585-994-0139-8 unknown Springer Morrison, K.; Engebretson, M. J.; Beck, J. R.; Johnson, J. E.; Arnoldy, R. L.; Cahill, L. J.; Carpenter, D. L.; Gallani, M. 1994 A study of quasi-periodic ELF-VLF emissions at three Antarctic stations: evidence for off-equatorial generation? Annales Geophysicae, 12 (2). 139-146. https://doi.org/10.1007/s00585-994-0139-8 <https://doi.org/10.1007/s00585-994-0139-8> Publication - Article PeerReviewed 1994 ftnerc https://doi.org/10.1007/s00585-994-0139-8 2023-02-04T19:44:43Z The spatial extent and temporal behaviour of quasi-periodic (QP) intensity modulations of 0.5-2 kHz ELF-VLF signals were investigated in a comparative study of data collected at the Antarctic stations of South Pole (L=14), Halley (L=4), and Siple (L=4). Frequently, the waveforms of ELF-VLF signals simultaneously received at each site were identical. Although of similar frequency structure, the waveforms of the accompanying Pc3 magnetic pulsations did not show a one-to-one association. Whereas both are dayside phenomena, QP emissions occur over a smaller range of local times, and have a maximum of occurrence later in the day closer to local noon. QP emissions are identified with the periodic modulation of the electron pitch-angle distribution by the propagation of ULF compressional fast-mode waves through a region. However, contrary to previous ideas, rising-tone emissions do not represent the frequency-time signatures of such waves. In addition to generation close to the equatorial plane, we propose an additional high-latitude source of QP emissions. These emissions are associated with regions of minimum B produced by the dayside compression of the magnetosphere close to the magnetopause. Model magnetic field calculations of these minimum-B regions as a function of magnetic local time and invariant latitude are presented. Article in Journal/Newspaper Antarc* Antarctic South pole South pole Natural Environment Research Council: NERC Open Research Archive Antarctic The Antarctic South Pole Siple ENVELOPE(-83.917,-83.917,-75.917,-75.917) Annales Geophysicae 12 2/3 139 146 |
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Open Polar |
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Natural Environment Research Council: NERC Open Research Archive |
op_collection_id |
ftnerc |
language |
unknown |
description |
The spatial extent and temporal behaviour of quasi-periodic (QP) intensity modulations of 0.5-2 kHz ELF-VLF signals were investigated in a comparative study of data collected at the Antarctic stations of South Pole (L=14), Halley (L=4), and Siple (L=4). Frequently, the waveforms of ELF-VLF signals simultaneously received at each site were identical. Although of similar frequency structure, the waveforms of the accompanying Pc3 magnetic pulsations did not show a one-to-one association. Whereas both are dayside phenomena, QP emissions occur over a smaller range of local times, and have a maximum of occurrence later in the day closer to local noon. QP emissions are identified with the periodic modulation of the electron pitch-angle distribution by the propagation of ULF compressional fast-mode waves through a region. However, contrary to previous ideas, rising-tone emissions do not represent the frequency-time signatures of such waves. In addition to generation close to the equatorial plane, we propose an additional high-latitude source of QP emissions. These emissions are associated with regions of minimum B produced by the dayside compression of the magnetosphere close to the magnetopause. Model magnetic field calculations of these minimum-B regions as a function of magnetic local time and invariant latitude are presented. |
format |
Article in Journal/Newspaper |
author |
Morrison, K. Engebretson, M. J. Beck, J. R. Johnson, J. E. Arnoldy, R. L. Cahill, L. J. Carpenter, D. L. Gallani, M. |
spellingShingle |
Morrison, K. Engebretson, M. J. Beck, J. R. Johnson, J. E. Arnoldy, R. L. Cahill, L. J. Carpenter, D. L. Gallani, M. A study of quasi-periodic ELF-VLF emissions at three Antarctic stations: evidence for off-equatorial generation? |
author_facet |
Morrison, K. Engebretson, M. J. Beck, J. R. Johnson, J. E. Arnoldy, R. L. Cahill, L. J. Carpenter, D. L. Gallani, M. |
author_sort |
Morrison, K. |
title |
A study of quasi-periodic ELF-VLF emissions at three Antarctic stations: evidence for off-equatorial generation? |
title_short |
A study of quasi-periodic ELF-VLF emissions at three Antarctic stations: evidence for off-equatorial generation? |
title_full |
A study of quasi-periodic ELF-VLF emissions at three Antarctic stations: evidence for off-equatorial generation? |
title_fullStr |
A study of quasi-periodic ELF-VLF emissions at three Antarctic stations: evidence for off-equatorial generation? |
title_full_unstemmed |
A study of quasi-periodic ELF-VLF emissions at three Antarctic stations: evidence for off-equatorial generation? |
title_sort |
study of quasi-periodic elf-vlf emissions at three antarctic stations: evidence for off-equatorial generation? |
publisher |
Springer |
publishDate |
1994 |
url |
http://nora.nerc.ac.uk/id/eprint/516689/ https://doi.org/10.1007/s00585-994-0139-8 |
long_lat |
ENVELOPE(-83.917,-83.917,-75.917,-75.917) |
geographic |
Antarctic The Antarctic South Pole Siple |
geographic_facet |
Antarctic The Antarctic South Pole Siple |
genre |
Antarc* Antarctic South pole South pole |
genre_facet |
Antarc* Antarctic South pole South pole |
op_relation |
Morrison, K.; Engebretson, M. J.; Beck, J. R.; Johnson, J. E.; Arnoldy, R. L.; Cahill, L. J.; Carpenter, D. L.; Gallani, M. 1994 A study of quasi-periodic ELF-VLF emissions at three Antarctic stations: evidence for off-equatorial generation? Annales Geophysicae, 12 (2). 139-146. https://doi.org/10.1007/s00585-994-0139-8 <https://doi.org/10.1007/s00585-994-0139-8> |
op_doi |
https://doi.org/10.1007/s00585-994-0139-8 |
container_title |
Annales Geophysicae |
container_volume |
12 |
container_issue |
2/3 |
container_start_page |
139 |
op_container_end_page |
146 |
_version_ |
1766251655824670720 |