ERA

Download the full-sized PDF of ULF Waves in the Magnetosphere and their Association with Magnetopause Instabilities and OscillationsDownload the full-sized PDF

Analytics

Share

Permanent link (DOI): https://doi.org/10.7939/R31620

Download

Export to: EndNote  |  Zotero  |  Mendeley

Communities

This file is in the following communities:

Graduate Studies and Research, Faculty of

Collections

This file is in the following collections:

Theses and Dissertations

ULF Waves in the Magnetosphere and their Association with Magnetopause Instabilities and Oscillations Open Access

Descriptions

Other title
Subject/Keyword
MHD model for ULF
Solar wind driver
Phase coherence
Magnetopsheric ULF waves
FLR harmonics
Open field lines
SuperDARN
discrete frequency FLR
Magnetopause Instabilities and Oscillations
KHI excitation
Type of item
Thesis
Degree grantor
University of Alberta
Author or creator
Nedie, Abiyu Z
Supervisor and department
Rankin, Robert (Physics)
Fenrich, Frances (Physics)
Examining committee member and department
Rankin, Robert (Physics)
Sydora, Richard (Physics)
Fenrich, Frances (Physics)
Tsui, Ying (Electrical Engineering)
Koustov, Sasha (Physics), University of Saskatoon
Department
Department of Physics
Specialization

Date accepted
2012-09-28T14:09:43Z
Graduation date
2012-09
Degree
Doctor of Philosophy
Degree level
Doctoral
Abstract
This thesis addresses the question of excitation of ULF waves by magnetopause instabilities and oscillations. Given proper spacecraft orientations and near magnetopause encounters, the CLUSTER spacecraft mission is used to resolve the space-time ambiguity inherent in a single spacecraft measurements. A case study is presented where a driver ULF wave is identified in the solar wind and on open field lines in association with a Field Line Resonance (FLR). This is one of the rare examples where a solar wind source has been unambiguously identified and causally linked with excitation of a FLR at the same frequency. It adds to a database of observations that can be used to determine the statistical relationship between various sources of ULF plasma waves and FLRs. It is also one of the few observations of a driver wave on open field lines by SuperDARN, and encourages further use of SuperDARN in that regard. In the second case study, a ULF wave signature at 1.7 mHz is observed just outside the magnetopause using CLUSTER and compared with fluctuations at ionospheric altitudes and on the ground. It is shown that ULF fluctuations at the magnetopause coincide with discrete frequency oscillations in HF radars, magnetometers and spacecraft inside the magnetosphere. The Poynting vector and phase propagation outward from the magnetopause, and the absence of a source in the solar wind, suggest a KHI generated surface mode as a source mechanism. A third case study presents a magnetopause oscillation resulting from a direct solar wind driver that transfers energy from the solar wind into FLRs. We observe a quasi-monochromatic 2.5 mHz discrete wave oscillation in IMF By. The dusk signature of the wave shows magnetic field and plasma flow oscillations at the magnetopause at the same discrete frequency. The SuperDARN Saskatoon radar in the pre-dawn sector reveals the footprint of an FLR structure with anti-sunward phase propagation that is linked to the solar wind driven magnetopause oscillation. This is the first work using SuperDARN that relates a solar wind driven magnetopause oscillation with a discrete frequency FLR in the magnetosphere. The thesis concludes by presenting results from a 2D ideal MHD wave model that is successful in qualitatively reproducing observed structure of FLRs for both KHI-like drivers and solar wind-driven magnetopause oscillations.
Language
English
DOI
doi:10.7939/R31620
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.
Citation for previous publication
Nedie, A. Z., R. Rankin, and F. R. Fenrich (2012), SuperDARN observations of the driver wave associated with FLRs, J. Geophys. Res., (117), A06232, doi:10.1029/2011JA017387.

File Details

Date Uploaded
Date Modified
2014-04-29T15:42:18.682+00:00
Audit Status
Audits have not yet been run on this file.
Characterization
File format: pdf (Portable Document Format)
Mime type: application/pdf
File size: 4737299
Last modified: 2015:10:18 01:37:50-06:00
Filename: Nedie_Abiyu_Fall2012.pdf
Original checksum: cb252646d23b31c4201bfe9aa5843da6
Well formed: false
Valid: false
Status message: Lexical error offset=4665698
File title: ULF Waves in the Magnetosphere and their Association with Magnetopause Instabilities and Oscillations
File author: Abiyu Zerfu Nedie
Page count: 177
Activity of users you follow
User Activity Date