Which cusp upflow events can possibly turn into outflows?
Two sequences, before and after magnetic noon, respectively, of poleward moving auroral forms with associated upflows situated above the European Incoherent Scatter Svalbard Radar allowed close study of ion upflow dynamics. We find that flux intensity is correlated with plasma temperature and that u...
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ftoslouniv:oai:www.duo.uio.no:10852/58732 2023-05-15T18:29:48+02:00 Which cusp upflow events can possibly turn into outflows? Skjæveland, Åsmund Moen, Jøran Idar Carlson, Herbert C. 2014 http://hdl.handle.net/10852/58732 http://urn.nb.no/URN:NBN:no-61533 https://doi.org/10.1002/2013JA019495 en eng Skjæveland, Åsmund (2017) Energy inputs and upward motion in the cusp. Doctoral thesis. http://hdl.handle.net/10852/58733 http://hdl.handle.net/10852/58733 http://urn.nb.no/URN:NBN:no-61533 http://hdl.handle.net/10852/58732 Journal of Geophysical Research - Space Physics 119 8 6876 6890 https://doi.org/10.1002/2013JA019495 URN:NBN:no-61533 Fulltext https://www.duo.uio.no/bitstream/handle/10852/58732/1/Skjaveland_et_al-2014.pdf Journal article Tidsskriftartikkel Peer reviewed PublishedVersion 2014 ftoslouniv https://doi.org/10.1002/2013JA019495 2020-06-21T08:51:06Z Two sequences, before and after magnetic noon, respectively, of poleward moving auroral forms with associated upflows situated above the European Incoherent Scatter Svalbard Radar allowed close study of ion upflow dynamics. We find that flux intensity is correlated with plasma temperature and that upflowing plasma undergoes acceleration proportional to the slope of the velocity profile and to the velocity at each altitude. The potential for upflows to lift thermal plasma to regions where broadband extremely low frequency electric field activity can cause nonthermal acceleration leading to outflow is examined. Equations for estimating the travel time of upflowing plasma are presented. We find that around 40% of the observed upflow profiles with a unit number flux greater than 1 × 1013 m−2 s−1 can transport plasma from 500 to 800 km altitude in less than 10 min, approximately the typical lifetime of pulsed upflow events. Almost all such profiles can transport plasma from 600 to 800 km in the same time span. Typical transport times for other altitude ranges are also presented. Post magnetic noon the background electron density was somewhat higher than prenoon due to transport of EUV-enhanced plasma, and the postnoon ion flux was somewhat weaker than prenoon. Article in Journal/Newspaper Svalbard Universitet i Oslo: Digitale utgivelser ved UiO (DUO) Svalbard Journal of Geophysical Research: Space Physics 119 8 6876 6890 |
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Open Polar |
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Universitet i Oslo: Digitale utgivelser ved UiO (DUO) |
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ftoslouniv |
language |
English |
description |
Two sequences, before and after magnetic noon, respectively, of poleward moving auroral forms with associated upflows situated above the European Incoherent Scatter Svalbard Radar allowed close study of ion upflow dynamics. We find that flux intensity is correlated with plasma temperature and that upflowing plasma undergoes acceleration proportional to the slope of the velocity profile and to the velocity at each altitude. The potential for upflows to lift thermal plasma to regions where broadband extremely low frequency electric field activity can cause nonthermal acceleration leading to outflow is examined. Equations for estimating the travel time of upflowing plasma are presented. We find that around 40% of the observed upflow profiles with a unit number flux greater than 1 × 1013 m−2 s−1 can transport plasma from 500 to 800 km altitude in less than 10 min, approximately the typical lifetime of pulsed upflow events. Almost all such profiles can transport plasma from 600 to 800 km in the same time span. Typical transport times for other altitude ranges are also presented. Post magnetic noon the background electron density was somewhat higher than prenoon due to transport of EUV-enhanced plasma, and the postnoon ion flux was somewhat weaker than prenoon. |
format |
Article in Journal/Newspaper |
author |
Skjæveland, Åsmund Moen, Jøran Idar Carlson, Herbert C. |
spellingShingle |
Skjæveland, Åsmund Moen, Jøran Idar Carlson, Herbert C. Which cusp upflow events can possibly turn into outflows? |
author_facet |
Skjæveland, Åsmund Moen, Jøran Idar Carlson, Herbert C. |
author_sort |
Skjæveland, Åsmund |
title |
Which cusp upflow events can possibly turn into outflows? |
title_short |
Which cusp upflow events can possibly turn into outflows? |
title_full |
Which cusp upflow events can possibly turn into outflows? |
title_fullStr |
Which cusp upflow events can possibly turn into outflows? |
title_full_unstemmed |
Which cusp upflow events can possibly turn into outflows? |
title_sort |
which cusp upflow events can possibly turn into outflows? |
publishDate |
2014 |
url |
http://hdl.handle.net/10852/58732 http://urn.nb.no/URN:NBN:no-61533 https://doi.org/10.1002/2013JA019495 |
geographic |
Svalbard |
geographic_facet |
Svalbard |
genre |
Svalbard |
genre_facet |
Svalbard |
op_relation |
Skjæveland, Åsmund (2017) Energy inputs and upward motion in the cusp. Doctoral thesis. http://hdl.handle.net/10852/58733 http://hdl.handle.net/10852/58733 http://urn.nb.no/URN:NBN:no-61533 http://hdl.handle.net/10852/58732 Journal of Geophysical Research - Space Physics 119 8 6876 6890 https://doi.org/10.1002/2013JA019495 URN:NBN:no-61533 Fulltext https://www.duo.uio.no/bitstream/handle/10852/58732/1/Skjaveland_et_al-2014.pdf |
op_doi |
https://doi.org/10.1002/2013JA019495 |
container_title |
Journal of Geophysical Research: Space Physics |
container_volume |
119 |
container_issue |
8 |
container_start_page |
6876 |
op_container_end_page |
6890 |
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1766213200701816832 |