Plasma structure within poleward-moving cusp/cleft auroral transients: EISCAT Svalbard radar observations and an explanation in terms of large local time extent of events
We report high-resolution observations of the southward-IMF cusp/cleft ionosphere made on December 16th 1998 by the EISCAT (European incoherent scatter) Svalbard radar (ESR), and compare them with observations of dayside auroral luminosity, as seen at a wavelength of 630 nm by a meridian scanning ph...
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ftleicesterunfig:oai:figshare.com:article/10182029 2023-05-15T16:04:39+02:00 Plasma structure within poleward-moving cusp/cleft auroral transients: EISCAT Svalbard radar observations and an explanation in terms of large local time extent of events M. Lockwood I. W. McCrea Stephen E. Milan J. Moen J. C. Cerisier A. Thorolfsson 2000-09-01T00:00:00Z https://figshare.com/articles/journal_contribution/Plasma_structure_within_poleward-moving_cusp_cleft_auroral_transients_EISCAT_Svalbard_radar_observations_and_an_explanation_in_terms_of_large_local_time_extent_of_events/10182029 unknown 2381/31901 https://figshare.com/articles/journal_contribution/Plasma_structure_within_poleward-moving_cusp_cleft_auroral_transients_EISCAT_Svalbard_radar_observations_and_an_explanation_in_terms_of_large_local_time_extent_of_events/10182029 All Rights Reserved Uncategorized Science & Technology Physical Sciences Astronomy & Astrophysics Geosciences Multidisciplinary Meteorology & Atmospheric Sciences Geology ionosphere polar ionosphere magnetospheric physics magnetopause cusp and boundary layers solar wind-magnetosphere interactions INTERPLANETARY MAGNETIC-FIELD FLUX-TRANSFER EVENTS PULSED MAGNETOPAUSE RECONNECTION FRICTIONAL HEATING EVENTS HIGH-LATITUDE IONOSPHERE CUSP ION PRECIPITATION CUTLASS FINLAND RADAR DAYSIDE IONOSPHERE SOLAR-WIND POLAR CUSP Text Journal contribution 2000 ftleicesterunfig 2021-11-11T19:53:58Z We report high-resolution observations of the southward-IMF cusp/cleft ionosphere made on December 16th 1998 by the EISCAT (European incoherent scatter) Svalbard radar (ESR), and compare them with observations of dayside auroral luminosity, as seen at a wavelength of 630 nm by a meridian scanning photometer at Ny Ålesund, and of plasma flows, as seen by the CUTLASS (co-operative UK twin location auroral sounding system) Finland HF radar. The optical data reveal a series of poleward-moving transient red-line (630 nm) enhancements, events that have been associated with bursts in the rate of magnetopause reconnection generating new open flux. The combined observations at this time have strong similarities to predictions of the effects of soft electron precipitation modulated by pulsed reconnection, as made by Davis and Lockwood (1996); however, the effects of rapid zonal flow in the ionosphere, caused by the magnetic curvature force on the newly opened field lines, are found to be a significant additional factor. In particular, it is shown how enhanced plasma loss rates induced by the rapid convection can explain two outstanding anomalies of the 630 nm transients, namely how minima in luminosity form between the poleward-moving events and how events can re-brighten as they move poleward. The observations show how cusp/cleft aurora and transient poleward-moving auroral forms appear in the ESR data and the conditions which cause enhanced 630 nm emission in the transients: they are an important first step in enabling the ESR to identify these features away from the winter solstice when supporting auroral observations are not available. Other Non-Article Part of Journal/Newspaper EISCAT Ny Ålesund Ny-Ålesund Svalbard University of Leicester: Figshare Lockwood ENVELOPE(167.400,167.400,-84.150,-84.150) Ny-Ålesund Svalbard |
institution |
Open Polar |
collection |
University of Leicester: Figshare |
op_collection_id |
ftleicesterunfig |
language |
unknown |
topic |
Uncategorized Science & Technology Physical Sciences Astronomy & Astrophysics Geosciences Multidisciplinary Meteorology & Atmospheric Sciences Geology ionosphere polar ionosphere magnetospheric physics magnetopause cusp and boundary layers solar wind-magnetosphere interactions INTERPLANETARY MAGNETIC-FIELD FLUX-TRANSFER EVENTS PULSED MAGNETOPAUSE RECONNECTION FRICTIONAL HEATING EVENTS HIGH-LATITUDE IONOSPHERE CUSP ION PRECIPITATION CUTLASS FINLAND RADAR DAYSIDE IONOSPHERE SOLAR-WIND POLAR CUSP |
spellingShingle |
Uncategorized Science & Technology Physical Sciences Astronomy & Astrophysics Geosciences Multidisciplinary Meteorology & Atmospheric Sciences Geology ionosphere polar ionosphere magnetospheric physics magnetopause cusp and boundary layers solar wind-magnetosphere interactions INTERPLANETARY MAGNETIC-FIELD FLUX-TRANSFER EVENTS PULSED MAGNETOPAUSE RECONNECTION FRICTIONAL HEATING EVENTS HIGH-LATITUDE IONOSPHERE CUSP ION PRECIPITATION CUTLASS FINLAND RADAR DAYSIDE IONOSPHERE SOLAR-WIND POLAR CUSP M. Lockwood I. W. McCrea Stephen E. Milan J. Moen J. C. Cerisier A. Thorolfsson Plasma structure within poleward-moving cusp/cleft auroral transients: EISCAT Svalbard radar observations and an explanation in terms of large local time extent of events |
topic_facet |
Uncategorized Science & Technology Physical Sciences Astronomy & Astrophysics Geosciences Multidisciplinary Meteorology & Atmospheric Sciences Geology ionosphere polar ionosphere magnetospheric physics magnetopause cusp and boundary layers solar wind-magnetosphere interactions INTERPLANETARY MAGNETIC-FIELD FLUX-TRANSFER EVENTS PULSED MAGNETOPAUSE RECONNECTION FRICTIONAL HEATING EVENTS HIGH-LATITUDE IONOSPHERE CUSP ION PRECIPITATION CUTLASS FINLAND RADAR DAYSIDE IONOSPHERE SOLAR-WIND POLAR CUSP |
description |
We report high-resolution observations of the southward-IMF cusp/cleft ionosphere made on December 16th 1998 by the EISCAT (European incoherent scatter) Svalbard radar (ESR), and compare them with observations of dayside auroral luminosity, as seen at a wavelength of 630 nm by a meridian scanning photometer at Ny Ålesund, and of plasma flows, as seen by the CUTLASS (co-operative UK twin location auroral sounding system) Finland HF radar. The optical data reveal a series of poleward-moving transient red-line (630 nm) enhancements, events that have been associated with bursts in the rate of magnetopause reconnection generating new open flux. The combined observations at this time have strong similarities to predictions of the effects of soft electron precipitation modulated by pulsed reconnection, as made by Davis and Lockwood (1996); however, the effects of rapid zonal flow in the ionosphere, caused by the magnetic curvature force on the newly opened field lines, are found to be a significant additional factor. In particular, it is shown how enhanced plasma loss rates induced by the rapid convection can explain two outstanding anomalies of the 630 nm transients, namely how minima in luminosity form between the poleward-moving events and how events can re-brighten as they move poleward. The observations show how cusp/cleft aurora and transient poleward-moving auroral forms appear in the ESR data and the conditions which cause enhanced 630 nm emission in the transients: they are an important first step in enabling the ESR to identify these features away from the winter solstice when supporting auroral observations are not available. |
format |
Other Non-Article Part of Journal/Newspaper |
author |
M. Lockwood I. W. McCrea Stephen E. Milan J. Moen J. C. Cerisier A. Thorolfsson |
author_facet |
M. Lockwood I. W. McCrea Stephen E. Milan J. Moen J. C. Cerisier A. Thorolfsson |
author_sort |
M. Lockwood |
title |
Plasma structure within poleward-moving cusp/cleft auroral transients: EISCAT Svalbard radar observations and an explanation in terms of large local time extent of events |
title_short |
Plasma structure within poleward-moving cusp/cleft auroral transients: EISCAT Svalbard radar observations and an explanation in terms of large local time extent of events |
title_full |
Plasma structure within poleward-moving cusp/cleft auroral transients: EISCAT Svalbard radar observations and an explanation in terms of large local time extent of events |
title_fullStr |
Plasma structure within poleward-moving cusp/cleft auroral transients: EISCAT Svalbard radar observations and an explanation in terms of large local time extent of events |
title_full_unstemmed |
Plasma structure within poleward-moving cusp/cleft auroral transients: EISCAT Svalbard radar observations and an explanation in terms of large local time extent of events |
title_sort |
plasma structure within poleward-moving cusp/cleft auroral transients: eiscat svalbard radar observations and an explanation in terms of large local time extent of events |
publishDate |
2000 |
url |
https://figshare.com/articles/journal_contribution/Plasma_structure_within_poleward-moving_cusp_cleft_auroral_transients_EISCAT_Svalbard_radar_observations_and_an_explanation_in_terms_of_large_local_time_extent_of_events/10182029 |
long_lat |
ENVELOPE(167.400,167.400,-84.150,-84.150) |
geographic |
Lockwood Ny-Ålesund Svalbard |
geographic_facet |
Lockwood Ny-Ålesund Svalbard |
genre |
EISCAT Ny Ålesund Ny-Ålesund Svalbard |
genre_facet |
EISCAT Ny Ålesund Ny-Ålesund Svalbard |
op_relation |
2381/31901 https://figshare.com/articles/journal_contribution/Plasma_structure_within_poleward-moving_cusp_cleft_auroral_transients_EISCAT_Svalbard_radar_observations_and_an_explanation_in_terms_of_large_local_time_extent_of_events/10182029 |
op_rights |
All Rights Reserved |
_version_ |
1766400262236274688 |