Variations in the altitude of the F2 peak associated with trough-formation processes
A novel approach is described which can help to determine, from ground-based data, which of the possible production mechanisms for the mid-latitude F-region ionospheric trough is dominant during a particular event. This approach involves numerically modelling the possible causal mechanisms of th...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
1996-06-01
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| Series: | Annales Geophysicae |
| Online Access: | https://www.ann-geophys.net/14/628/1996/angeo-14-628-1996.pdf |
| _version_ | 1819229208585437184 |
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| author | R. I. Crickmore B. Jenkins G. J. Bailey |
| author_facet | R. I. Crickmore B. Jenkins G. J. Bailey |
| author_sort | R. I. Crickmore |
| collection | DOAJ |
| description | A novel approach is described which can help
to determine, from ground-based data, which of the possible production
mechanisms for the mid-latitude F-region ionospheric trough is dominant during a
particular event. This approach involves numerically modelling the possible
causal mechanisms of the mid-latitude trough to see how each will affect the
altitude of the F2-layer electron-concentration peak (hmF2), and then comparing
these predictions with the observed variation of hmF2 during trough formation.
The modelling work predicts that, if the neutral-wind velocity does not vary,
hmF2 will remain almost constant if the trough is formed via stagnation, but
will rise if it is formed as a result of high ion velocities or neutral
upwelling. Observations made at Halley (76°S, 27°W, <i>L</i>=4.2), Antarctica,
show that most frequently the only changes in hmF2 during trough formation are
those expected due to variations in the neutral wind, which suggests that
stagnation is the most common production mechanism. During the most
geomagnetically active night studied, on which Ap varied between 18 and 32,
there was a rise in hmF2 that cannot be explained by changes in the neutral
wind. On this night the plasma also decayed faster, and the poleward edge of the
trough was seen earlier than on other nights. These differences, together with
the fact that the ion velocities remained relatively low, suggest the trough was
caused by a change in neutral composition, possibly advected into the observing
area. |
| first_indexed | 2024-12-23T11:09:31Z |
| format | Article |
| id | doaj.art-a02c2ae3aef3463cb2d88bec756020c4 |
| institution | Directory Open Access Journal |
| issn | 0992-7689 1432-0576 |
| language | English |
| last_indexed | 2024-12-23T11:09:31Z |
| publishDate | 1996-06-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Annales Geophysicae |
| spelling | doaj.art-a02c2ae3aef3463cb2d88bec756020c42022-12-21T17:49:24ZengCopernicus PublicationsAnnales Geophysicae0992-76891432-05761996-06-011462863610.1007/s00585-996-0628-zVariations in the altitude of the F2 peak associated with trough-formation processesR. I. CrickmoreB. JenkinsG. J. BaileyA novel approach is described which can help to determine, from ground-based data, which of the possible production mechanisms for the mid-latitude F-region ionospheric trough is dominant during a particular event. This approach involves numerically modelling the possible causal mechanisms of the mid-latitude trough to see how each will affect the altitude of the F2-layer electron-concentration peak (hmF2), and then comparing these predictions with the observed variation of hmF2 during trough formation. The modelling work predicts that, if the neutral-wind velocity does not vary, hmF2 will remain almost constant if the trough is formed via stagnation, but will rise if it is formed as a result of high ion velocities or neutral upwelling. Observations made at Halley (76°S, 27°W, <i>L</i>=4.2), Antarctica, show that most frequently the only changes in hmF2 during trough formation are those expected due to variations in the neutral wind, which suggests that stagnation is the most common production mechanism. During the most geomagnetically active night studied, on which Ap varied between 18 and 32, there was a rise in hmF2 that cannot be explained by changes in the neutral wind. On this night the plasma also decayed faster, and the poleward edge of the trough was seen earlier than on other nights. These differences, together with the fact that the ion velocities remained relatively low, suggest the trough was caused by a change in neutral composition, possibly advected into the observing area.https://www.ann-geophys.net/14/628/1996/angeo-14-628-1996.pdf |
| spellingShingle | R. I. Crickmore B. Jenkins G. J. Bailey Variations in the altitude of the F2 peak associated with trough-formation processes Annales Geophysicae |
| title | Variations in the altitude of the F2 peak associated with trough-formation processes |
| title_full | Variations in the altitude of the F2 peak associated with trough-formation processes |
| title_fullStr | Variations in the altitude of the F2 peak associated with trough-formation processes |
| title_full_unstemmed | Variations in the altitude of the F2 peak associated with trough-formation processes |
| title_short | Variations in the altitude of the F2 peak associated with trough-formation processes |
| title_sort | variations in the altitude of the f2 peak associated with trough formation processes |
| url | https://www.ann-geophys.net/14/628/1996/angeo-14-628-1996.pdf |
| work_keys_str_mv | AT ricrickmore variationsinthealtitudeofthef2peakassociatedwithtroughformationprocesses AT bjenkins variationsinthealtitudeofthef2peakassociatedwithtroughformationprocesses AT gjbailey variationsinthealtitudeofthef2peakassociatedwithtroughformationprocesses |