SuperDARN Observations of High Latitude Electrodynamics in the Terrestrial Ionosphere
thesis
posted on 2021-09-15, 09:05 authored by Alexandra Ruth FoggCoupling of the solar wind and interplanetary magnetic field to the terrestrial
system results in a dynamic magnetosphere-ionosphere interaction, full of complexity
yet to be unravelled. In this thesis, high latitude electrodynamics will
be examined in relation to solar wind - magnetosphere - ionosphere coupling,
primarily by observations from the Super Dual Auroral Radar Network (Super-
DARN). SuperDARN is made up of, at time of writing, over 35 high frequency
coherent scatter radars, which provide near global coverage of the geomagnetic
poles. Originally conceived to measure ionospheric convection, the SuperDARN
dataset can be assimilated into minute resolution electrostatic potential solutions,
known as ionospheric convection maps, which are the primary diagnostic tool in
this thesis. The quality of the derived equipotential maps is dependent on a variety
of processing stages, including the determination of the low latitude limit
of the convection pattern. Firstly, a new method for determining the position of
this boundary is presented, based on an examination of the relationship between
the scale sizes of the convection and field aligned current (FAC) regions. A linear
relationship is demonstrated, which can be used, incorporating independent FAC
measurements, to estimate a scatter independent measure of the low latitude
limit of the convection region. Finally, the effects of the impact of solar wind
pressure pulses on the terrestrial ionosphere will be examined. If the pressure
pulse compresses the magnetosphere but does not trigger a geomagnetic storm,
this is known as a positive sudden impulse. Enhancements in dayside driving of
the ionosphere following the onset of a positive sudden impulse will be presented
both in the form of a detailed case study, and statistically using a superposed
epoch analysis. For the first time, simultaneous measurements of ionospheric
convection and FACs will be utilised to observe the effects of this phenomenon.
History
Supervisor(s)
Mark Lester; Timothy YeomanDate of award
2021-03-15Author affiliation
Department of Physics and AstronomyAwarding institution
University of LeicesterQualification level
- Doctoral
Qualification name
- PhD
Language
enUsage metrics
Categories
No categories selectedLicence
Exports
RefWorks
BibTeX
Ref. manager
Endnote
DataCite
NLM
DC