St Andrews Research Repository

St Andrews University Home
View Item 
  •   St Andrews Research Repository
  • Mathematics & Statistics (School of)
  • Mathematics & Statistics Theses
  • View Item
  •   St Andrews Research Repository
  • Mathematics & Statistics (School of)
  • Mathematics & Statistics Theses
  • View Item
  •   St Andrews Research Repository
  • Mathematics & Statistics (School of)
  • Mathematics & Statistics Theses
  • View Item
  • Login
JavaScript is disabled for your browser. Some features of this site may not work without it.

Field line resonances in the earth's magnetosphere driven by convectively unstable magnetospheric waveguide modes

Thumbnail
View/Open
MairiMcRobbiePhdThesis.pdf (54.73Mb)
Date
07/2002
Author
McRobbie, Mairi Catriona
Supervisor
Wright, Andrew
Funder
Particle Physics and Astronomy Research Council (PPARC)
University of St Andrews
Metadata
Show full item record
Altmetrics Handle Statistics
Abstract
Shear flow instabilities, such as Kelvin-Helmholtz instabilities, occurring on the Earth’s magnetospheric flanks may cause fast magnetosonic wave modes to propagate through the non-homogeneous environment of the Earth’s magnetospheric cavity. The non-uniformity in this plasma environment means the fast wave mode couples to a standing Alfvén wave mode along a closed field line in the magnetosphere with natural frequency equal to the fast wave frequency. The one-dimensional hydromagnetic box model of Southwood (1974), which treats the Earth’s magnetic field as a set of straight field lines between two ionospheric boundaries which are not perfectly reflecting, is used to model the resonance. There is a finite height-integrated Pedersen conductivity, Σp, at the boundaries of the one-dimensional box which is responsible for the damping of the field line resonance. The coupling process between the fast and Alfvén modes is represented by a simple harmonic oscillator equation driven by a time-dependent function representing the fast mode azimuthal pressure gradient, Wright (1992a,b). A fourth-order Runge-Kutta numerical integration technique is used to obtain the solution to the simple harmonic oscillation. These numerical routines are verified using analytically derived solutions for a test case of a simple driving function d{t) = Dsin(wdt). Following this test of the numerical routines, realistic driving functions from Wright et al (2002), which represent convectively unstable fast wave modes propagating through the magnetospheric cavity as a result of a Kelvin-Helmholtz instability occurring on the flanks of the magnetosphere, are used to drive the simple harmonic system. Four different unstable drivers are used, these being the fundamental and the second harmonic mode for two different values of azimuthal coordinate. For all four drivers clear resonance characteristics emerged, suggesting these may drive field line resonances in the Earth’s magnetosphere.
Type
Thesis, MPhil Master of Philosophy
Collections
  • Mathematics & Statistics Theses
URI
http://hdl.handle.net/10023/11303

Items in the St Andrews Research Repository are protected by copyright, with all rights reserved, unless otherwise indicated.

Advanced Search

Browse

All of RepositoryCommunities & CollectionsBy Issue DateNamesTitlesSubjectsClassificationTypeFunderThis CollectionBy Issue DateNamesTitlesSubjectsClassificationTypeFunder

My Account

Login

Open Access

To find out how you can benefit from open access to research, see our library web pages and Open Access blog. For open access help contact: openaccess@st-andrews.ac.uk.

Accessibility

Read our Accessibility statement.

How to submit research papers

The full text of research papers can be submitted to the repository via Pure, the University's research information system. For help see our guide: How to deposit in Pure.

Electronic thesis deposit

Help with deposit.

Repository help

For repository help contact: Digital-Repository@st-andrews.ac.uk.

Give Feedback

Cookie policy

This site may use cookies. Please see Terms and Conditions.

Usage statistics

COUNTER-compliant statistics on downloads from the repository are available from the IRUS-UK Service. Contact us for information.

© University of St Andrews Library

University of St Andrews is a charity registered in Scotland, No SC013532.

  • Facebook
  • Twitter