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Permanent link (DOI): https://doi.org/10.7939/R3KW57S25

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Open-Closed Magnetic Field Line Boundary Identification Using Directional Derivatives of SuperDARN Convection Flow Open Access

Descriptions

Other title
Subject/Keyword
SuperDARN
Open-Closed Field Line Boundary
Directional derivative technique
Type of item
Thesis
Degree grantor
University of Alberta
Author or creator
Hoque, SNM A
Supervisor and department
Fenrich, Frances (Physics)
Examining committee member and department
Currie, Claire (Physics)
Rozmus, Wojciech (Physics)
McWilliams, Kathryn (Physics and Engineering Physics)
Marchand, Richard (Physics)
Chow, Kim (Physics)
Department
Department of Physics
Specialization

Date accepted
2014-11-26T14:19:47Z
Graduation date
2015-06
Degree
Doctor of Philosophy
Degree level
Doctoral
Abstract
This thesis is a case study analysis to better understand magnetospheric dynamics and in particular dynamics of the open-closed magnetic field line boundary (OCB). The directional derivatives of ionospheric convection flow speed are measured along streamlines using SuperDARN HF radar to determine the open-closed magnetic field line boundary (OCB). It is found that the peak in the directional derivative of SuperDARN flow along a flow streamline may be associated with magnetic reconnection between open and closed field lines and thus is a signature of the OCB.In the first case study, the peak in the directional derivative of SuperDARN flow is compared in all magnetic local time sectors with other OCB proxies such as ultra-violet auroral emission boundaries and particle precipitation boundaries during the southward interplanetary magnetic field condition. The OCB proxy determined with the the directional derivative of SuperDARN flow is found to be consistent with other OCB proxies during the interval. In the second case study, the proposed technique is further evaluated during two different substorm events, with each event interval lasting two hours. The latitudinal locations of the peak in the directional derivative of SuperDARN flow are in agreement with the spectrographic imager’s poleward boundaries of ultra-violet emissions in the dawn and dusk sectors during the substorm intervals. In the final part of the thesis, multiple peaks in the directional derivative of flow during the substorm interval are examined and compared with ultraviolet detectors in the midnight sector. The occurrence of multiple flow peaks in the directional derivative of flow depends on the convection cell pattern which in turn depends upon the IMF By condition. The result indicates that the secondary peaks agree with the ultraviolet measurements in the midnight sector. Therefore, SuperDARN convection flow directional derivatives might be useful for determining the OCB globally.
Language
English
DOI
doi:10.7939/R3KW57S25
Rights
Permission is hereby granted to the University of Alberta Libraries to reproduce single copies of this thesis and to lend or sell such copies for private, scholarly or scientific research purposes only. Where the thesis is converted to, or otherwise made available in digital form, the University of Alberta will advise potential users of the thesis of these terms. The author reserves all other publication and other rights in association with the copyright in the thesis and, except as herein before provided, neither the thesis nor any substantial portion thereof may be printed or otherwise reproduced in any material form whatsoever without the author's prior written permission.
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