Multi-instrument study of the dynamic cusp during dominant IMF B y conditions
We present multi-instrument observations using the meridian scanning photometer (MSP) at NyAlesund, the EISCAT Svalbard radar (ESR) and the CUTLASS Finland HF radar, to investigate the dynamics of the cusp region during pulsed reconnection events. The optical data obtained from the MSP indicate the...
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ftdoajarticles:oai:doaj.org/article:d2339240441847268a1c60a3dca16aa4 2023-05-15T16:04:49+02:00 Multi-instrument study of the dynamic cusp during dominant IMF B y conditions H. Khan M. Lester J. A. Davies S. E. Milan P. E. Sandholt 2003-03-01T00:00:00Z https://doi.org/10.5194/angeo-21-693-2003 https://doaj.org/article/d2339240441847268a1c60a3dca16aa4 EN eng Copernicus Publications https://www.ann-geophys.net/21/693/2003/angeo-21-693-2003.pdf https://doaj.org/toc/0992-7689 https://doaj.org/toc/1432-0576 doi:10.5194/angeo-21-693-2003 0992-7689 1432-0576 https://doaj.org/article/d2339240441847268a1c60a3dca16aa4 Annales Geophysicae, Vol 21, Pp 693-708 (2003) Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 article 2003 ftdoajarticles https://doi.org/10.5194/angeo-21-693-2003 2022-12-31T16:03:02Z We present multi-instrument observations using the meridian scanning photometer (MSP) at NyAlesund, the EISCAT Svalbard radar (ESR) and the CUTLASS Finland HF radar, to investigate the dynamics of the cusp region during pulsed reconnection events. The optical data obtained from the MSP indicate the presence of several poleward-moving auroral forms (PMAFs) which have been previously identified as the auroral signature of pulsed reconnection. Furthermore, the optical green line (557.7 nm) luminosity indicates a loss of emission equatorward of the location of the onset of the PMAFs, characteristic of magnetospheric plasma escaping to the magnetosheath along newly opened field lines. This reduction in green line luminosity creates a "dark region", the equatorward edge of which is found to lie close to the boundary between high and low spectral widths observed by the CUTLASS Finland radar. High spectral widths on the dayside have previously been identified as a good indicator of cusp backscatter. Both of these boundaries have been suggested to provide an accurate representation of the location of the open/closed field line boundary. The ESR observations show enhancements in electron density and electron temperature occurring in conjunction with the optical PMAFs. The observations demonstrate some correspondence with the theoretical predictions of Davis and Lockwood (1996), who used an auroral precipitation model to predict ESR observations in the vicinity of the cusp. However, the limitations of this model are apparent under conditions of large plasma flows in the ionosphere. Finally, convection velocities obtained from the HF radar data illustrate a flow regime similar to that predicted to be driven by strong IMF B y , as described by Cowley and Lockwood (1992), demonstrating an initial azimuthal flow followed by a rotation to more poleward directions. Key words. Ionosphere (ionosphere-magnetosphere interactions; particle precipitation) – Magnetospheric physics (magnetopause, cusp and boundary layers) Article in Journal/Newspaper EISCAT Svalbard Directory of Open Access Journals: DOAJ Articles Cowley ENVELOPE(-134.909,-134.909,60.518,60.518) Lockwood ENVELOPE(167.400,167.400,-84.150,-84.150) Svalbard Annales Geophysicae 21 3 693 708 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 |
spellingShingle |
Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 H. Khan M. Lester J. A. Davies S. E. Milan P. E. Sandholt Multi-instrument study of the dynamic cusp during dominant IMF B y conditions |
topic_facet |
Science Q Physics QC1-999 Geophysics. Cosmic physics QC801-809 |
description |
We present multi-instrument observations using the meridian scanning photometer (MSP) at NyAlesund, the EISCAT Svalbard radar (ESR) and the CUTLASS Finland HF radar, to investigate the dynamics of the cusp region during pulsed reconnection events. The optical data obtained from the MSP indicate the presence of several poleward-moving auroral forms (PMAFs) which have been previously identified as the auroral signature of pulsed reconnection. Furthermore, the optical green line (557.7 nm) luminosity indicates a loss of emission equatorward of the location of the onset of the PMAFs, characteristic of magnetospheric plasma escaping to the magnetosheath along newly opened field lines. This reduction in green line luminosity creates a "dark region", the equatorward edge of which is found to lie close to the boundary between high and low spectral widths observed by the CUTLASS Finland radar. High spectral widths on the dayside have previously been identified as a good indicator of cusp backscatter. Both of these boundaries have been suggested to provide an accurate representation of the location of the open/closed field line boundary. The ESR observations show enhancements in electron density and electron temperature occurring in conjunction with the optical PMAFs. The observations demonstrate some correspondence with the theoretical predictions of Davis and Lockwood (1996), who used an auroral precipitation model to predict ESR observations in the vicinity of the cusp. However, the limitations of this model are apparent under conditions of large plasma flows in the ionosphere. Finally, convection velocities obtained from the HF radar data illustrate a flow regime similar to that predicted to be driven by strong IMF B y , as described by Cowley and Lockwood (1992), demonstrating an initial azimuthal flow followed by a rotation to more poleward directions. Key words. Ionosphere (ionosphere-magnetosphere interactions; particle precipitation) – Magnetospheric physics (magnetopause, cusp and boundary layers) |
format |
Article in Journal/Newspaper |
author |
H. Khan M. Lester J. A. Davies S. E. Milan P. E. Sandholt |
author_facet |
H. Khan M. Lester J. A. Davies S. E. Milan P. E. Sandholt |
author_sort |
H. Khan |
title |
Multi-instrument study of the dynamic cusp during dominant IMF B y conditions |
title_short |
Multi-instrument study of the dynamic cusp during dominant IMF B y conditions |
title_full |
Multi-instrument study of the dynamic cusp during dominant IMF B y conditions |
title_fullStr |
Multi-instrument study of the dynamic cusp during dominant IMF B y conditions |
title_full_unstemmed |
Multi-instrument study of the dynamic cusp during dominant IMF B y conditions |
title_sort |
multi-instrument study of the dynamic cusp during dominant imf b y conditions |
publisher |
Copernicus Publications |
publishDate |
2003 |
url |
https://doi.org/10.5194/angeo-21-693-2003 https://doaj.org/article/d2339240441847268a1c60a3dca16aa4 |
long_lat |
ENVELOPE(-134.909,-134.909,60.518,60.518) ENVELOPE(167.400,167.400,-84.150,-84.150) |
geographic |
Cowley Lockwood Svalbard |
geographic_facet |
Cowley Lockwood Svalbard |
genre |
EISCAT Svalbard |
genre_facet |
EISCAT Svalbard |
op_source |
Annales Geophysicae, Vol 21, Pp 693-708 (2003) |
op_relation |
https://www.ann-geophys.net/21/693/2003/angeo-21-693-2003.pdf https://doaj.org/toc/0992-7689 https://doaj.org/toc/1432-0576 doi:10.5194/angeo-21-693-2003 0992-7689 1432-0576 https://doaj.org/article/d2339240441847268a1c60a3dca16aa4 |
op_doi |
https://doi.org/10.5194/angeo-21-693-2003 |
container_title |
Annales Geophysicae |
container_volume |
21 |
container_issue |
3 |
container_start_page |
693 |
op_container_end_page |
708 |
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1766400460190646272 |