Density duct formation in the wake of a travelling ionospheric disturbance: Murchison Widefield Array observations
©2016. American Geophysical Union. Geomagnetically aligned density structures with a range of sizes exist in the near-Earth plasma environment, including 10-100 km wide VLF/HF wave-ducting structures. Their small diameters and modest density enhancements make them difficult to observe, and there is...
| Main Authors: | , , , , , , , , , , |
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| Format: | Journal Article |
| Published: |
Wiley-Blackwell Publishing
2016
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| Online Access: | http://hdl.handle.net/20.500.11937/23256 |
| _version_ | 1848751099418247168 |
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| author | Loi, S. Cairns, I. Murphy, T. Erickson, P. Bell, M. Rowlinson, A. Arora, Balwinder Singh Morgan, John Ekers, Ronald Hurley-Walker, Natasha Kaplan, D. |
| author_facet | Loi, S. Cairns, I. Murphy, T. Erickson, P. Bell, M. Rowlinson, A. Arora, Balwinder Singh Morgan, John Ekers, Ronald Hurley-Walker, Natasha Kaplan, D. |
| author_sort | Loi, S. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | ©2016. American Geophysical Union. Geomagnetically aligned density structures with a range of sizes exist in the near-Earth plasma environment, including 10-100 km wide VLF/HF wave-ducting structures. Their small diameters and modest density enhancements make them difficult to observe, and there is limited evidence for any of the several formation mechanisms proposed to date. We present a case study of an event on 26 August 2014 where a travelling ionospheric disturbance (TID) shortly precedes the formation of a complex collection of field-aligned ducts, using data obtained by the Murchison Widefield Array (MWA) radio telescope. Their spatiotemporal proximity leads us to suggest a causal interpretation. Geomagnetic conditions were quiet at the time, and no obvious triggers were noted. Growth of the structures proceeds rapidly, within 0.5 h of the passage of the TID, attaining their peak prominence 1-2 h later and persisting for several more hours until observations ended at local dawn. Analyses of the next 2 days show field-aligned structures to be preferentially detectable under quiet rather than active geomagnetic conditions. We used a raster scanning strategy facilitated by the speed of electronic beamforming to expand the quasi-instantaneous field of view of the MWA by a factor of 3. These observations represent the broadest angular coverage of the ionosphere by a radio telescope to date. |
| first_indexed | 2025-11-14T07:47:20Z |
| format | Journal Article |
| id | curtin-20.500.11937-23256 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T07:47:20Z |
| publishDate | 2016 |
| publisher | Wiley-Blackwell Publishing |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-232562017-09-13T13:57:03Z Density duct formation in the wake of a travelling ionospheric disturbance: Murchison Widefield Array observations Loi, S. Cairns, I. Murphy, T. Erickson, P. Bell, M. Rowlinson, A. Arora, Balwinder Singh Morgan, John Ekers, Ronald Hurley-Walker, Natasha Kaplan, D. ©2016. American Geophysical Union. Geomagnetically aligned density structures with a range of sizes exist in the near-Earth plasma environment, including 10-100 km wide VLF/HF wave-ducting structures. Their small diameters and modest density enhancements make them difficult to observe, and there is limited evidence for any of the several formation mechanisms proposed to date. We present a case study of an event on 26 August 2014 where a travelling ionospheric disturbance (TID) shortly precedes the formation of a complex collection of field-aligned ducts, using data obtained by the Murchison Widefield Array (MWA) radio telescope. Their spatiotemporal proximity leads us to suggest a causal interpretation. Geomagnetic conditions were quiet at the time, and no obvious triggers were noted. Growth of the structures proceeds rapidly, within 0.5 h of the passage of the TID, attaining their peak prominence 1-2 h later and persisting for several more hours until observations ended at local dawn. Analyses of the next 2 days show field-aligned structures to be preferentially detectable under quiet rather than active geomagnetic conditions. We used a raster scanning strategy facilitated by the speed of electronic beamforming to expand the quasi-instantaneous field of view of the MWA by a factor of 3. These observations represent the broadest angular coverage of the ionosphere by a radio telescope to date. 2016 Journal Article http://hdl.handle.net/20.500.11937/23256 10.1002/2015JA022052 Wiley-Blackwell Publishing fulltext |
| spellingShingle | Loi, S. Cairns, I. Murphy, T. Erickson, P. Bell, M. Rowlinson, A. Arora, Balwinder Singh Morgan, John Ekers, Ronald Hurley-Walker, Natasha Kaplan, D. Density duct formation in the wake of a travelling ionospheric disturbance: Murchison Widefield Array observations |
| title | Density duct formation in the wake of a travelling ionospheric disturbance: Murchison Widefield Array observations |
| title_full | Density duct formation in the wake of a travelling ionospheric disturbance: Murchison Widefield Array observations |
| title_fullStr | Density duct formation in the wake of a travelling ionospheric disturbance: Murchison Widefield Array observations |
| title_full_unstemmed | Density duct formation in the wake of a travelling ionospheric disturbance: Murchison Widefield Array observations |
| title_short | Density duct formation in the wake of a travelling ionospheric disturbance: Murchison Widefield Array observations |
| title_sort | density duct formation in the wake of a travelling ionospheric disturbance: murchison widefield array observations |
| url | http://hdl.handle.net/20.500.11937/23256 |